Merge pull request 'README + danctnix-besser-pkgbuild/README: point at kernel-agent pkgrel=4 flow' (#21) from noether/readme-pkgrel4-kernel-agent-flow into main

Reviewed-on: #21

README.md

@@ -53,6 +53,9 @@ CW1200-ancestry markers in current source: same author Dmitry Tarnyagin,
 |------|------|
 | **This umbrella** | `git.reauktion.de/marfrit/besser` — patches/, scripts/, fw-analysis/, notes/ |
 | **Mobian DKMS fork** (PR target) | `git.reauktion.de/marfrit/bes2600-dkms` — branches per patch; upstream = `salsa.debian.org/Mobian-team/devices/bes2600-dkms` |
+| **DanctNIX kernel package** (ohm) | `git.reauktion.de/marfrit/marfrit-packages/arch/linux-pinetab2-danctnix-besser/` — kernel-agent-driven PKGBUILD, pkgrel=4+ |
+| **kernel-agent manifest + patches** | `git.reauktion.de/marfrit/kernel-agent` — `fleet/ohm.yaml` lists the per-patch series, `bin/ka-promote ohm` emits the cumulative the PKGBUILD consumes |
+| **Historical hand-managed PKGBUILD** | `git.reauktion.de/marfrit/besser/danctnix-besser-pkgbuild/` — pkgrel≤3, deprecated; see directory README |
 
 ## Patch series
 

danctnix-besser-pkgbuild/README.md

@@ -0,0 +1,222 @@
+# linux-pinetab2-danctnix-besser
+
+Soft-upstream fork of `linux-pinetab2` (DanctNIX kernel for PineTab2) carrying the **BESser** bes2600 staging-driver patchset.
+
+Drop-in replacement for `linux-pinetab2`. Same kernel version, same config (one toggle aside — see SCS caveat below), same modules — only the `drivers/staging/bes2600/` driver differs.
+
+---
+
+> ## ⚠️ PKGBUILD MOVED
+>
+> Starting with **pkgrel=4** (2026-05-18), the canonical PKGBUILD lives at
+> **`git.reauktion.de/marfrit/marfrit-packages/arch/linux-pinetab2-danctnix-besser/`**
+> and is driven by [kernel-agent](https://git.reauktion.de/marfrit/kernel-agent)'s
+> `ka-promote ohm` cumulative-patch flow against `fleet/ohm.yaml`.
+>
+> This directory remains for historical reference (pkgrel=1..3 hand-managed
+> flow + per-patch design notes that haven't been ported to the new home yet).
+>
+> **Use the new location** for builds going forward. See
+> [kernel-agent PR #28](https://git.reauktion.de/marfrit/kernel-agent/pulls/28)
+> and [marfrit-packages PR #28](https://git.reauktion.de/marfrit/marfrit-packages/pulls/28)
+> for the migration.
+
+---
+
+## TL;DR
+
+| | |
+|---|---|
+| **Current package** | `linux-pinetab2-danctnix-besser-7.0.danctnix1-5-aarch64.pkg.tar.zst` (built via [kernel-agent](https://git.reauktion.de/marfrit/kernel-agent)) |
+| **PKGBUILD home** | `git.reauktion.de/marfrit/marfrit-packages/arch/linux-pinetab2-danctnix-besser/` *(new — pkgrel=4 onwards)* |
+| **Patch manifest** | `git.reauktion.de/marfrit/kernel-agent` `fleet/ohm.yaml` |
+| **Cumulative b2sum** | `0eb091ddaba4a8f1c3c2a78…` (pkgrel=5, `ka-promote ohm` output, 162 704 B, 4 patches) |
+| **Module srcversion** | `BEB625FA7443171EA8D55F7` for pkgrel=4 (byte-identical to pkgrel=3 source). pkgrel=5 srcversion differs because the besser#18 fix is bundled (TBD pending build verification). |
+| **Kernel base** | DanctNIX [`linux-pinetab2`](https://codeberg.org/DanctNIX/linux-pinetab2) tag `v7.0-danctnix1` |
+| **What it fixes vs upstream** | +73 % TX throughput, the `wsm_generic_confirm 0x0007` dmesg storm (besser#1 closed), the firmware-PSM-not-honored hang, the multi-function SDIO LMAC-wedge recovery |
+| **What it adds today vs pkgrel=1** | **Patch I**: 5 GHz scan filter — `iw scan freq <single-5ghz-channel>` works, multi-channel per-band sweep refused at driver boundary to dodge firmware reject cascade. NM `band=a` profiles associate to 5 GHz cleanly. **Sustained 11.32 MB/s** download (2.54 GB factory image) on `newton` 5 GHz ch.48 — **3.6× the 2.4 GHz baseline of 3.12 MB/s** on the same source. |
+| **Source-of-truth (driver)** | `git.reauktion.de/marfrit/bes2600-dkms` — branch `cleanups` for c-stack+A+B, branch `bes2600/scan-filter-5ghz` for Patch I |
+| **Caveat** | `CONFIG_SHADOW_CALL_STACK=n` (security-hardening regression, workaround for a GCC 15.2.1 + arm_neon.h pragma issue — tracked in [besser#20](https://git.reauktion.de/marfrit/besser/issues/20), restore to `=y` when GCC is fixed) |
+
+## pkgrel history
+
+| pkgrel | Date | Flow | Notes |
+|---|---|---|---|
+| 1–3 | 2026-05-08…05-18 | hand-managed, this dir | c-stack + Patches A/B/C/D/E/F/G/H + Patch I + SCS Makefile workaround |
+| 4 | 2026-05-18 | kernel-agent (`ka-promote ohm`) | migration-only release: byte-identical source to pkgrel=3 (148 149 + 7 735 + 1 562 = 157 446 cumulative arithmetic); fixes pkgrel=3 PKGBUILD's duplicated `0003-...patch` source-array bug. Available as fallback. |
+| **5** | **2026-05-18** | **kernel-agent (`ka-promote ohm`)** | adds [besser#18](https://git.reauktion.de/marfrit/besser/issues/18) lockdep fix (pending_record_lock SOFTIRQ-safe → -unsafe inversion). 4-patch cumulative, 162 704 B, b2sum `0eb091ddaba4…`. Closes besser#18 + besser#1. |
+
+---
+
+## What's in the patchset
+
+A 17-commit cumulative diff over `v7.0-danctnix1`'s in-tree `drivers/staging/bes2600/`, plus the standalone Patch I (5 GHz scan filter) and an arm64 build-environment workaround for GCC 15.
+
+Individual commits with full rationale + Phase-7 verification logs live on the **`cleanups` branch** of [`marfrit/bes2600-dkms`](https://git.reauktion.de/marfrit/bes2600-dkms/commits/branch/cleanups) and the **`bes2600/scan-filter-5ghz` branch** for Patch I. This PKGBUILD ships them squashed into separate patch files for build atomicity.
+
+| group | what it does |
+|---|---|
+| **c-stack (c5.1–c5.2.1, c6.1, c6.2, c7)** | wifi-stability fixes: scan-defer-on-firmware-reject, scan-defer-backoff-tune, LMAC recover via `mmc_hw_reset`, PM state resync, wake-state consume, firmware-doesn't-honour-PSM self-detect, multi-function SDIO `mmc_hw_reset` rescan |
+| **Patch A** | decrypt-storm fast-recover at `bes2600_rx_cb`: ≥5 `WSM_STATUS_DECRYPTFAILURE` in 5 s → `ieee80211_connection_loss(vif)`. Phase-7 confirmed N=2 (2026-05-07), storms recover ~1 s vs 109 s baseline. |
+| **Patch B** | connection-loss bus-reset: ≥3 driver-side connection-loss decisions in 60 s on the same vif → `mmc_hw_reset` instead of mac80211 reauth. Installed dormant; never tripped in production yet. |
+| **Patch C v3** | structural: drop `sdio_rx_work` workqueue relay; IRQ → bh-direct architecture (matches mainline cw1200). +73 % sustained RX. |
+| **Patch D** | `ba_lock` removed; `ba_acc/ba_cnt/ba_acc_rx/ba_cnt_rx/ba_ena` → `atomic_t`; per-RX-frame spinlock eliminated. |
+| **Patch E** | per-RX-frame `ps_state_lock` skipped when c7's `pm_unsupported` latch is on (steady-state on production firmware). |
+| **Patch F** | cw1200 mainline backports: hw_scan SKB-lifecycle UAF, `init_common` `destroy_workqueue` on error, `atomic_add(1, x) → atomic_inc(x)` cosmetic. |
+| **Patch G** | GPL-2.0 §1 attribution restoration: SPDX-License-Identifier on every file, Tarnyagin/ST-Ericsson copyright restored on cw1200-derived files. |
+| **Patch C2** | `ieee80211_rx_irqsafe → ieee80211_rx_ni` at all 6 sites (kernel.org-clean process-context API; tasklet hop removed). |
+| **Patch H** | `bh.c` hygiene cleanup: 76- and 468-line `#if 0` cw1200-ancestor fossil blocks removed; `__bes2600_irq_enable` stub removed; per-iteration `BUG_ON` → `WARN_ON_ONCE`. |
+| **Patch I** ([besser#1](https://git.reauktion.de/marfrit/besser/issues/1)) | **5 GHz scan filter.** Refuses only **multi-channel** 5 GHz scans (the per-band-sweep mac80211 issues internally) at the driver boundary with `-EOPNOTSUPP`, dodging the firmware's status-2 reject cascade. Single-channel 5 GHz scans pass through so NM/`wpa_supplicant` per-freq BSS discovery (when `802-11-wireless.band=a`) still finds and associates to 5 GHz APs. Net effect: dmesg storm gone, 5 GHz attachment works, 3.6× sustained throughput on 5 GHz HT40 vs 2.4 GHz HT20. |
+| **arm64 SCS Makefile workaround** | Adds `-ffixed-x18` explicitly for `arch/arm64/lib/xor-neon.o` when `CONFIG_SHADOW_CALL_STACK=y`. Dead code in this pkgrel (SCS is off), in place for the day SCS re-enable becomes possible. See [besser#20](https://git.reauktion.de/marfrit/besser/issues/20). |
+
+## Measured outcome
+
+- **Phase 7 (Patch I, 2026-05-18):** Pattern A `wsm_generic_confirm failed for request 0x0007` storm: 14.3/h → **0/h** over 30-min observation. 5 GHz `newton` BSSID `c0:25:06:e6:5b:33` @ 5240 MHz (ch.48), TX bitrate 150 Mbit/s MCS 7 HT40 short-GI. Internet download throughput **11.32 MB/s** (sustained 90.5 Mbit/s, ~60 % of PHY) vs 3.12 MB/s on 2.4 GHz HT20 same source.
+- **Phase 7 (Patch C v3 + F + G + D + E + C2 + H, Mobian-flavor):** N=3 stress @ 4 MB/s sender on RK3566/PineTab2 — Patch B baseline 1.36 MB/s → +73 % sustained 2.28 MB/s. Race-fix verified under stress (no `wsm_release_tx_buffer` WARN storm under load).
+- Module loads + associates cleanly; `pm_unsupported` latch fires on boot as expected.
+
+## Building (pkgrel=4+, kernel-agent flow)
+
+Builds run out of the new home:
+
+```sh
+cd ~/src/marfrit-packages/arch/linux-pinetab2-danctnix-besser
+makepkg -s
+```
+
+To refresh the cumulative patch from a new kernel-agent manifest state:
+
+```sh
+cd ~/src/kernel-agent
+./bin/ka-promote ohm
+cp build/ohm/v7.0-danctnix1/cumulative.patch \
+   ~/src/marfrit-packages/arch/linux-pinetab2-danctnix-besser/0001-bes2600-besser-kernel-agent-cumulative.patch
+cp build/ohm/v7.0-danctnix1/manifest.lock \
+   ~/src/marfrit-packages/arch/linux-pinetab2-danctnix-besser/manifest.lock
+b2sum 0001-bes2600-besser-kernel-agent-cumulative.patch  # update PKGBUILD b2sums and pkgrel
+```
+
+## Building (pkgrel ≤ 3, hand-managed flow — DEPRECATED)
+
+```sh
+cd ~/src/besser/marfrit-besser/danctnix-besser-pkgbuild/kernel
+makepkg -s
+```
+
+Produces `linux-pinetab2-danctnix-besser-<ver>-aarch64.pkg.tar.zst` plus a matching `-headers` package. Build host can be aarch64 native (recommended — no cross-toolchain setup) or x86 with an aarch64 cross-compiler.
+
+Build time: ~45–55 min on an 8-core aarch64 host (boltzmann/RPi5-class), most of it the kernel modules phase.
+
+**GCC 15.2.1 note:** This pkgrel ships with `CONFIG_SHADOW_CALL_STACK=n` because GCC 15.2.1's strict pragma validator chokes on `arm_neon.h`'s push/`target("+nothing+aes")`/pop sequences when SCS is on. The `0003-arm64-xor-neon-ffixed-x18-build-fix.patch` is a defensive Makefile-side workaround that's a no-op while SCS is off; it'll silently unblock SCS=y once GCC upstream is fixed. See [besser#20](https://git.reauktion.de/marfrit/besser/issues/20) for the re-enable plan.
+
+## Installing
+
+The package declares `provides=("linux-pinetab2=$pkgver-$pkgrel")` and `conflicts=(linux-pinetab2)`, so `pacman` will cleanly take over from upstream `linux-pinetab2`:
+
+```sh
+sudo pacman -U linux-pinetab2-danctnix-besser-7.0.danctnix1-5-aarch64.pkg.tar.zst
+```
+
+That removes the upstream `linux-pinetab2` package (if installed) and registers the BESser-flavored kernel under the same provides slot. Headers package is optional; install it if you build out-of-tree modules.
+
+The pacman `mkinitcpio` hook auto-generates `/boot/initramfs-linux-pinetab2-danctnix-besser.img`. Modules land in `/usr/lib/modules/<release>-pinetab2-danctnix-besser/`, vmlinuz at `/boot/vmlinuz-linux-pinetab2-danctnix-besser`, DTBs at `/boot/dtbs/rockchip/rk3566-pinetab2-{v0.1,v2.0}.dtb`.
+
+### Bootloader (PineTab2-specific)
+
+PineTab2 boots via U-Boot loading a script `boot.scr` (compiled from `/boot/boot.txt` via `mkscr`). After install, point the script at the new kernel + initramfs:
+
+```sh
+sudo cp /boot/boot.txt /boot/boot.txt.pre-besser
+sudo cp /boot/boot.scr /boot/boot.scr.pre-besser
+sudo sed -i \
+  -e 's|/vmlinuz-linux-pinetab2$|/vmlinuz-linux-pinetab2-danctnix-besser|' \
+  -e 's|/initramfs-linux-pinetab2\.img|/initramfs-linux-pinetab2-danctnix-besser.img|' \
+  /boot/boot.txt
+cd /boot && sudo ./mkscr
+sudo systemctl reboot
+```
+
+Backups (`*.pre-besser`) let you revert without touching the U-Boot console: `sudo cp /boot/boot.scr.pre-besser /boot/boot.scr` and reboot.
+
+## Verifying
+
+After reboot:
+
+```sh
+uname -r
+# expected: <kver>-pinetab2-danctnix-besser
+
+lsmod | grep -i bes2600
+# expected: bes2600 (loaded), bes2600_btuart (loaded if Bluetooth in use)
+
+cat /sys/module/bes2600/srcversion
+# expected: BEB625FA7443171EA8D55F7 for pkgrel=3 (and pkgrel=4 — byte-identical source)
+```
+
+`dmesg | grep bes2600` should show clean firmware load, no SDIO TX panic, no `wsm_release_tx_buffer` WARN storm under load, no `wsm_generic_confirm failed for request 0x0007` storm.
+
+For the 5 GHz fix specifically:
+```sh
+sudo iw dev wlan0 scan freq 5180
+# expected: completes, no "Operation not supported"
+
+sudo iw dev wlan0 scan freq 5180 5200 5220 5240
+# expected: "Operation not supported (-95)" — multi-channel 5 GHz refused
+```
+
+## Rolling back
+
+If the new kernel misbehaves:
+
+```sh
+sudo cp /boot/boot.scr.pre-besser /boot/boot.scr
+sudo systemctl reboot
+```
+
+That returns you to whatever kernel `boot.scr` was pointing at before the install (typically upstream `linux-pinetab2` or the previous `linux-pinetab2-danctnix-besser`). The package itself can be removed with `sudo pacman -R linux-pinetab2-danctnix-besser` and the original `linux-pinetab2` re-installed via `sudo pacman -S linux-pinetab2`.
+
+## Provenance
+
+- Mobian-flavor source-of-truth: <https://git.reauktion.de/marfrit/bes2600-dkms> (`cleanups` branch for c-stack + Patches A/B, `bes2600/scan-filter-5ghz` for Patch I)
+- Per-patch breakdown, Phase 0–7 logs, follow-up issues: <https://git.reauktion.de/marfrit/besser>
+- Upstream cw1200 mainline (architectural reference): `drivers/net/wireless/st/cw1200/` in linux-rockchip
+- Kernel base: <https://codeberg.org/DanctNIX/linux-pinetab2> tag `v7.0-danctnix1`
+- Kernel-agent mirror of the patch tree + per-host manifest: <https://git.reauktion.de/marfrit/kernel-agent>
+
+## Why it's "BESser"
+
+"Besser" = German for "better." Patch series ID across both DKMS (Mobian) and in-tree (Danctnix) trees. Single source-of-truth lives in `marfrit/bes2600-dkms`; this PKGBUILD is the danctnix-flavor consumption surface.
+
+## Soft-upstream intent
+
+Submitting this PKGBUILD to DanctNIX for review. If accepted as a replacement for `linux-pinetab2` (or sidegrade), the BESser patchset ships to all PineTab2 users via the regular danctnix package update channel. The bes2600 driver gets:
+
+- ~2× sustained RX throughput on 2.4 GHz
+- ~3.6× sustained RX throughput on 5 GHz (via Patch I + correctly using HT40)
+- Race-correctness on the hot path
+- GPL-2.0 §1 attribution compliance
+- Modern kernel API (no deprecated `from_timer`, no `_irqsafe` from process context, no `BUG_ON` in steady-state)
+
+Drop-in compatibility: same kernel version, same module names, no userspace ABI change. SCS off is the one config caveat, tracked in [besser#20](https://git.reauktion.de/marfrit/besser/issues/20).
+
+## Maintenance plan
+
+**Effective pkgrel=4+:** the per-host manifest in `marfrit/kernel-agent` (`fleet/ohm.yaml`) is the per-patch authority. `ka-promote ohm` produces the cumulative; the PKGBUILD in `marfrit/marfrit-packages` consumes it. Updates flow:
+
+- New danctnix kernel release → bump `baseline.ref` in `fleet/ohm.yaml`, re-promote, bump pkgver in marfrit-packages PKGBUILD.
+- New BESser patch → add a new series-dir in `kernel-agent/patches/driver/bes2600/`, add to `fleet/ohm.yaml` `includes:`, re-promote, refresh cumulative + b2sum in marfrit-packages PKGBUILD, bump pkgrel.
+- Both flavors continue to be maintained in lockstep via `marfrit/bes2600-dkms` source-of-truth.
+- GCC 15 SCS issue → periodically re-test build with `CONFIG_SHADOW_CALL_STACK=y` against current Arch ARM GCC. When the build succeeds, flip the config and re-deploy.
+
+## Known gaps
+
+- Cumulative diff (squashed) for the c-stack + Patches A/B; Patch I as a separate `0002-` file. Per-patch series can be regenerated if danctnix maintainers prefer.
+- Bluetooth-side `bes2600_btuart` is independent and untouched by this patchset.
+- `bes2600_switch_bt` orchestration removed (Mobian-only entry point; not used in danctnix tree).
+- Multi-band `iw scan` (no `freq` filter) still reports aborted scan because mac80211 aggregates per-band results and marks the whole scan aborted when any leg returns negative (mac80211 contract, not bes2600). Single-band scans (`iw scan freq 2462` or `iw scan freq 5180`) work normally; `nmcli connection up` with `band=bg` or `band=a` profile works normally. This is the Phase 5 reviewer's predicted residual limitation; userspace tools that need full multi-band BSS discovery should issue per-band scans.
+
+## Author
+
+Markus Fritsche <fritsche.markus@gmail.com>
+
+Built collaboratively with Claude Opus 4.7 (1M context).

danctnix-besser-pkgbuild/kernel/0002-bes2600-filter-5ghz-scan.patch

@@ -0,0 +1,168 @@
+From 093a5038b8b68f316d976b7cb69609ca7f24f322 Mon Sep 17 00:00:00 2001
+From: Markus Fritsche <fritsche.markus@gmail.com>
+Date: Mon, 18 May 2026 11:27:40 +0200
+Subject: [PATCH 1/2] bes2600: filter 5 GHz scans at the driver boundary
+ (besser#1)
+
+The BES2600 firmware refuses WSM start-scan for 5 GHz with status 2
+("rejected by policy").  This shows up in dmesg as the recurring
+
+    wsm_generic_confirm failed for request 0x0007.
+    [SCAN] Scan failed (-22).
+
+pattern (besser issue #1, ~14-16/h on ohm/PineTab2 baseline).
+
+Trace shows every reject is the second of a back-to-back pair: mac80211
+splits multi-band hw_scan requests per band when the driver does not
+set IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS (we don't), then re-invokes
+drv_hw_scan from __ieee80211_scan_completed for each subsequent band.
+The 2.4 GHz iteration succeeds; the 5 GHz iteration is what the
+firmware rejects.  See ieee80211_prep_hw_scan in net/mac80211/scan.c
+for the loop, and the existing memory reference_bes2600_5ghz_scan_reject
+for the firmware behaviour.
+
+The 056a71a defer-on-reject patch already in this tree handles the
+BT-A2DP-coex branch and the consecutive-reject backoff, but it cannot
+prevent the per-band-loop reject: by the time defer_should_scan is
+consulted, the per-band call is already in flight, and the reject_count
+gets reset on every successful 2.4 GHz scan in between (which is
+~36% of attempts), so the threshold never trips.
+
+The fix: refuse the 5 GHz iteration upfront in bes2600_hw_scan.  The
+2.4 GHz scan still runs normally.  The 5 GHz portion is reported as
+aborted to userspace -- same outcome as today, minus the dmesg storm
+and the wsm_generic_confirm WARN cascade.
+
+5 GHz band registration is intentionally left in place: direct-BSSID
+association to a known 5 GHz AP still works (no scan is needed for
+that path), and a future firmware update that fixes the scan behaviour
+should not be foreclosed by changing band advertisement.
+
+Contract: per include/net/mac80211.h ieee80211_ops.hw_scan, a negative
+return aborts the scan without requiring ieee80211_scan_completed().
+-EOPNOTSUPP is the semantically accurate code (operation is legal,
+driver can't service it on this band today).
+
+Phase 3 evidence:
+- baseline N=3: rate ~14.3-23.6/h converged at 14.3/h (matches OP)
+- back-to-back scan gap: 6/6 rejected pairs <200us, 1/1 successful
+  pair was 114ms (single-band-only, no 5 GHz leg)
+- defer log fires: 0/9 in 30-min window (056a71a structurally bypassed)
+
+Predicted Phase 7 delta: Pattern A 14/h -> 0/h.
+---
+ bes2600/scan.c | 22 ++++++++++++++++++++++
+ 1 file changed, 22 insertions(+)
+
+diff --git a/drivers/staging/bes2600/scan.c b/drivers/staging/bes2600/scan.c
+index fb1d298..a81afb6 100644
+--- a/drivers/staging/bes2600/scan.c
++++ b/drivers/staging/bes2600/scan.c
+@@ -238,6 +238,28 @@ int bes2600_hw_scan(struct ieee80211_hw *hw,
+ 	/* Scan when P2P_GO corrupt firmware MiniAP mode */
+ 	if (priv->join_status == BES2600_JOIN_STATUS_AP)
+ 		return -EOPNOTSUPP;
++
++	/*
++	 * Firmware refuses WSM start-scan for 5 GHz with status 2 ("rejected
++	 * by policy"); see besser issue #1.  mac80211 splits multi-band
++	 * hw_scan requests per-band when the driver does not set
++	 * IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS (we don't -- see
++	 * ieee80211_hw_set() calls in bes2600_main.c), so each per-band call
++	 * has req->channels[] from one band only (see ieee80211_prep_hw_scan
++	 * in net/mac80211/scan.c).  Refuse the 5 GHz iteration at the driver
++	 * boundary so userspace gets a clean aborted-scan for that portion
++	 * rather than waiting for the firmware reject to cascade up.  5 GHz
++	 * band registration stays intact so direct-BSSID association to a
++	 * known 5 GHz AP still works (no scan needed for that path).
++	 *
++	 * Contract: per include/net/mac80211.h struct ieee80211_ops.hw_scan
++	 * documentation, a negative return aborts the scan without requiring
++	 * ieee80211_scan_completed().
++	 */
++	if (req->n_channels > 0 &&
++	    req->channels[0]->band == NL80211_BAND_5GHZ)
++		return -EOPNOTSUPP;
++
+ #if 0
+ 	if (work_pending(&priv->offchannel_work) ||
+ 			(hw_priv->roc_if_id != -1)) {
+-- 
+2.54.0
+
+
+From 8cd10f487c8144d462a510812ba0fa717b3e24df Mon Sep 17 00:00:00 2001
+From: Markus Fritsche <fritsche.markus@gmail.com>
+Date: Mon, 18 May 2026 15:56:34 +0200
+Subject: [PATCH 2/2] bes2600: scan-filter-5ghz: allow targeted single-channel
+ scans (besser#1 follow-up)
+
+The original Patch I refused EVERY 5 GHz scan request unconditionally
+(req->n_channels > 0 && band == NL80211_BAND_5GHZ).  This eliminated
+the Pattern A storm but also broke 5 GHz association entirely:
+NM / wpa_supplicant iterates a freq_list when a connection profile
+specifies 802-11-wireless.band=a, issuing per-frequency single-channel
+scans to find the BSS before associating.  Those single-channel scans
+were also refused by our guard, so the BSS was never seen and
+'Wi-Fi network could not be found' was the only outcome.
+
+Tighten the guard: refuse only multi-channel 5 GHz scans (n_channels
+> 1), which is the per-band-sweep pattern mac80211 issues internally
+and the only one that triggers the firmware storm at the per-band
+loop boundary.  Single-channel 5 GHz scans pass through to firmware,
+which generally accepts them -- and when they happen to be rejected,
+the failure is isolated and doesn't cascade.
+
+Verified on ohm with pkgrel=3 (srcversion BEB625FA7443171EA8D55F7):
+  - Pattern A count since boot: 0 (Phase 7 prediction still holds)
+  - iw dev wlan0 scan freq 5180          -> allowed
+  - iw dev wlan0 scan freq 5180 5200 ... -> refused -EOPNOTSUPP
+  - NM 'nmcli connection up' with band=a -> associated to BSSID
+    c0:25:06:e6:5b:33 on 5240 MHz / ch.48 in ~1 second
+  - TX bitrate 150 Mbit/s MCS 7 40MHz short-GI (vs 72.2 Mbit/s
+    HT20 on 2.4 GHz) -- ~2x throughput recovered
+
+The change is a single byte (> 0 -> > 1) plus comment update; the
+test confirmation above is what motivates it.
+
+Refs: besser#1 (closed but tracked for follow-up like this), original
+Patch I sha 093a503.
+---
+ bes2600/scan.c | 16 ++++++++++++----
+ 1 file changed, 12 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/staging/bes2600/scan.c b/drivers/staging/bes2600/scan.c
+index a81afb6..497523b 100644
+--- a/drivers/staging/bes2600/scan.c
++++ b/drivers/staging/bes2600/scan.c
+@@ -248,15 +248,23 @@ int bes2600_hw_scan(struct ieee80211_hw *hw,
+ 	 * has req->channels[] from one band only (see ieee80211_prep_hw_scan
+ 	 * in net/mac80211/scan.c).  Refuse the 5 GHz iteration at the driver
+ 	 * boundary so userspace gets a clean aborted-scan for that portion
+-	 * rather than waiting for the firmware reject to cascade up.  5 GHz
+-	 * band registration stays intact so direct-BSSID association to a
+-	 * known 5 GHz AP still works (no scan needed for that path).
++	 * rather than waiting for the firmware reject to cascade up.
++	 *
++	 * Only the multi-channel case is refused (n_channels > 1): that's
++	 * the per-band-sweep pattern mac80211 issues internally and the
++	 * one that triggers the firmware storm at the per-band loop
++	 * boundary.  Single-channel 5 GHz scans (BSS verification, NM's
++	 * per-freq iteration when 802-11-wireless.band=a is set) pass
++	 * through to firmware, which generally accepts them since the
++	 * storm is the back-to-back per-band issue, not a blanket 5 GHz
++	 * reject.  This preserves 5 GHz association via the
++	 * "wpa_supplicant iterates freq_list per channel" path.
+ 	 *
+ 	 * Contract: per include/net/mac80211.h struct ieee80211_ops.hw_scan
+ 	 * documentation, a negative return aborts the scan without requiring
+ 	 * ieee80211_scan_completed().
+ 	 */
+-	if (req->n_channels > 0 &&
++	if (req->n_channels > 1 &&
+ 	    req->channels[0]->band == NL80211_BAND_5GHZ)
+ 		return -EOPNOTSUPP;
+ 
+-- 
+2.54.0
+

danctnix-besser-pkgbuild/kernel/0003-arm64-xor-neon-ffixed-x18-build-fix.patch

@@ -0,0 +1,36 @@
+From: Markus Fritsche <fritsche.markus@gmail.com>
+Date: Mon, 18 May 2026 11:42:00 +0200
+Subject: [PATCH] arm64: xor-neon: restore -ffixed-x18 when SHADOW_CALL_STACK=y
+ (GCC 15+ build fix)
+
+GCC 15.2.1 enforces that -fsanitize=shadow-call-stack requires
+-ffixed-x18 inside arm_neon.h's #pragma GCC target() blocks.  The
+existing CFLAGS_REMOVE_xor-neon.o line strips the kernel-wide
+-ffixed-x18 (it's part of CC_FLAGS_NO_FPU) and CC_FLAGS_FPU does not
+restore it, so xor-neon.c fails to build on stricter GCC versions
+when CONFIG_SHADOW_CALL_STACK=y.
+
+Add an explicit -ffixed-x18 just for this object, gated on the
+SCS config so non-SCS builds are unaffected.
+
+Build environment workaround; not a kernel-runtime bug.
+---
+ arch/arm64/lib/Makefile | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile
+index 1234567..2345678 100644
+--- a/arch/arm64/lib/Makefile
++++ b/arch/arm64/lib/Makefile
+@@ -9,6 +9,10 @@ ifeq ($(CONFIG_KERNEL_MODE_NEON), y)
+ obj-$(CONFIG_XOR_BLOCKS)	+= xor-neon.o
+ CFLAGS_xor-neon.o		+= $(CC_FLAGS_FPU)
+ CFLAGS_REMOVE_xor-neon.o	+= $(CC_FLAGS_NO_FPU)
++# GCC 15+ enforces that -fsanitize=shadow-call-stack requires -ffixed-x18
++# even after a #pragma GCC pop_options inside arm_neon.h.  CC_FLAGS_REMOVE
++# above strips the kernel-wide -ffixed-x18 (part of CC_FLAGS_NO_FPU); add
++# it back here so xor-neon.c still compiles when SHADOW_CALL_STACK=y.
++CFLAGS_xor-neon.o		+= $(if $(CONFIG_SHADOW_CALL_STACK),-ffixed-x18)
+ endif
+ 
+ lib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o

danctnix-besser-pkgbuild/kernel/PKGBUILD

@@ -0,0 +1,236 @@
+# Maintainer: Markus Fritsche <fritsche.markus@gmail.com>
+# Forked from: linux-pinetab2 by Danct12 <danct12@disroot.org>
+# Original Contributor: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
+#
+# linux-pinetab2-danctnix-besser: linux-pinetab2 + the BESser
+# bes2600 driver patchset (race-fix, lock-removal, attribution-restore,
+# fossil-cleanup; +73% throughput vs the in-tree baseline).  Soft-upstream
+# fork of linux-pinetab2 — drop-in replacement, same kernel version, only
+# the bes2600 staging driver differs.  See git.reauktion.de/marfrit/besser
+# and git.reauktion.de/marfrit/bes2600-dkms for full provenance.
+
+pkgbase=linux-pinetab2-danctnix-besser
+pkgver=7.0.danctnix1
+pkgrel=3
+pkgdesc='PineTab2 (BESser bes2600 driver patchset)'
+_srcname=linux-pinetab2
+_srctag=v${pkgver%.*}-${pkgver##*.}
+arch=(aarch64)
+_url_git="https://codeberg.org/DanctNIX/${_srcname}"
+url="${_url_git}/commits/tag/$_srctag"
+license=(GPL-2.0-only)
+makedepends=(
+  bc
+  cpio
+  gettext
+  git
+  libelf
+  pahole
+  perl
+  python
+  tar
+  xz
+)
+options=(
+  !debug
+  !strip
+)
+source=(
+  https://cdn.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/linux-${pkgver%.*}.tar.{xz,sign}
+  ${_url_git}/releases/download/${_srctag}/${_srctag}.patch.zst{,.sig}
+  0001-bes2600-besser-cumulative-series.patch
+  0002-bes2600-filter-5ghz-scan.patch
+  0003-arm64-xor-neon-ffixed-x18-build-fix.patch
+  0003-arm64-xor-neon-ffixed-x18-build-fix.patch
+  config  # the main kernel config file
+)
+validpgpkeys=(
+  ABAF11C65A2970B130ABE3C479BE3E4300411886  # Linus Torvalds
+  647F28654894E3BD457199BE38DBBDC86092693E  # Greg Kroah-Hartman
+  F09A933C0FE0331E558CA4E166CAB7EAA45DD781  # Danct12
+)
+b2sums=('3d9795083c8938f80f480de0d10bfd9c525640e59d5c7f22983de3f12ee42c84c31be902cafb05579ddb1c32bac5ed06b0d4953f9705450be185bd2d9ab08f89'
+        'SKIP'
+        '71fe98221e802b315e54b4b10d3e8c8f376695a36bae3541d876e5776a37f3fa33c8f8dfa6e51fcbd6f5396add02e5166634165f2351836a0ea0453c172fe56c'
+        'SKIP'
+        'fca0a5badf762d5dbc085261cccc07ddeef96384d2ae0a426fb0412acd7a180e068cabd59f01342b7575d41889afc0f47dfbc9256801ab809f746278e6dab510'
+        '396acbdcf570eada62533c0b8f505ed18077e8432249bab5b8ac8d1107cabc9489bdb91a5780446237ec4fd9ba5fc57a49dff34c16ddab60dc30513fc535f00f'
+        '2714e3c0cd8ec978ce9431418f44f578220886fcabb738c9a0c43fc3c043753960b7c47ae96e1780154d8b266a2add6098407de4ffa7aee40d77ce17e8c70df9'
+        '2714e3c0cd8ec978ce9431418f44f578220886fcabb738c9a0c43fc3c043753960b7c47ae96e1780154d8b266a2add6098407de4ffa7aee40d77ce17e8c70df9'
+        '656a998ab40cb85ee4c00f087b071a91632a6c091da2c84b0f74236b51d2dea6e9db6886625f80ad81dc249d8494ec47cd79d6dd9ea4f5e44f3cde857f861e10')
+
+export KBUILD_BUILD_HOST=archlinux
+export KBUILD_BUILD_USER=$pkgbase
+export KBUILD_BUILD_TIMESTAMP="$(date -Ru${SOURCE_DATE_EPOCH:+d @$SOURCE_DATE_EPOCH})"
+
+prepare() {
+  cd linux-${pkgver%.*}
+
+  echo "Setting version..."
+  echo "-$pkgrel" > localversion.10-pkgrel
+  echo "${pkgbase#linux}" > localversion.20-pkgname
+
+  local src
+  for src in "${source[@]}"; do
+      src="${src%%::*}"
+      src="${src##*/}"
+      src="${src%.zst}"
+      [[ $src = *.patch ]] || continue
+      echo "Applying patch: $src..."
+      patch -Np1 < "../$src"
+  done
+
+  echo "Setting config..."
+  cp ../config .config
+  make olddefconfig
+  diff -u ../config .config || :
+
+  make -s kernelrelease > version
+  echo "Prepared $pkgbase version $(<version)"
+}
+
+build() {
+  cd linux-${pkgver%.*}
+  make DTC_FLAGS="-@" all
+  make -C tools/bpf/bpftool vmlinux.h feature-clang-bpf-co-re=1
+}
+
+_package() {
+  pkgdesc="The $pkgdesc kernel and modules"
+  depends=(
+    coreutils
+    kmod
+    mkinitcpio
+  )
+  optdepends=(
+    'wireless-regdb: to set the correct wireless channels of your country'
+    'linux-firmware: firmware images needed for some devices'
+  )
+  provides=(
+    KSMBD-MODULE
+    WIREGUARD-MODULE
+    "linux-pinetab2=$pkgver-$pkgrel"
+  )
+  conflicts=(linux-pinetab2)
+  replaces=(
+    wireguard-arch
+  )
+
+  cd linux-${pkgver%.*}
+  local modulesdir="$pkgdir/usr/lib/modules/$(<version)"
+
+  echo "Installing boot image..."
+  # systemd expects to find the kernel here to allow hibernation
+  # https://github.com/systemd/systemd/commit/edda44605f06a41fb86b7ab8128dcf99161d2344
+  install -Dm644 "$(make -s image_name)" "$modulesdir/vmlinuz"
+
+  # Used by mkinitcpio to name the kernel
+  echo "$pkgbase" | install -Dm644 /dev/stdin "$modulesdir/pkgbase"
+
+  echo "Installing modules..."
+  ZSTD_CLEVEL=19 make INSTALL_MOD_PATH="$pkgdir/usr" INSTALL_MOD_STRIP=1 \
+    DEPMOD=/doesnt/exist modules_install  # Suppress depmod
+
+  echo "Installing device trees..."
+  make INSTALL_DTBS_PATH="$pkgdir/boot/dtbs" dtbs_install
+
+  # Removing unnecessary device trees (keep only pinetab2 variants).
+  # Use find -delete instead of a bash for-loop: the previous for-loop
+  # silently no-op'd in the makepkg environment, leaving 234 unrelated
+  # board DTBs in the package.  find is robust to nullglob/cwd quirks.
+  find "$pkgdir"/boot/dtbs/rockchip/ -mindepth 1 -maxdepth 1 -type f \
+       ! -name 'rk3566-pinetab2-*' -delete
+
+  # remove build link
+  rm "$modulesdir"/build
+}
+
+_package-headers() {
+  pkgdesc="Headers and scripts for building modules for the $pkgdesc kernel"
+  depends=(pahole)
+
+  cd linux-${pkgver%.*}
+  local builddir="$pkgdir/usr/lib/modules/$(<version)/build"
+
+  echo "Installing build files..."
+  install -Dt "$builddir" -m644 .config Makefile Module.symvers System.map \
+    localversion.* version vmlinux tools/bpf/bpftool/vmlinux.h
+  install -Dt "$builddir/kernel" -m644 kernel/Makefile
+  install -Dt "$builddir/arch/arm64" -m644 arch/arm64/Makefile
+  cp -t "$builddir" -a scripts
+
+  # required when DEBUG_INFO_BTF_MODULES is enabled
+  install -Dt "$builddir/tools/bpf/resolve_btfids" tools/bpf/resolve_btfids/resolve_btfids
+
+  echo "Installing headers..."
+  cp -t "$builddir" -a include
+  cp -t "$builddir/arch/arm64" -a arch/arm64/include
+  install -Dt "$builddir/arch/arm64/kernel" -m644 arch/arm64/kernel/asm-offsets.s
+
+  install -Dt "$builddir/drivers/md" -m644 drivers/md/*.h
+  install -Dt "$builddir/net/mac80211" -m644 net/mac80211/*.h
+
+  # https://bugs.archlinux.org/task/13146
+  install -Dt "$builddir/drivers/media/i2c" -m644 drivers/media/i2c/msp3400-driver.h
+
+  # https://bugs.archlinux.org/task/20402
+  install -Dt "$builddir/drivers/media/usb/dvb-usb" -m644 drivers/media/usb/dvb-usb/*.h
+  install -Dt "$builddir/drivers/media/dvb-frontends" -m644 drivers/media/dvb-frontends/*.h
+  install -Dt "$builddir/drivers/media/tuners" -m644 drivers/media/tuners/*.h
+
+  # https://bugs.archlinux.org/task/71392
+  install -Dt "$builddir/drivers/iio/common/hid-sensors" -m644 drivers/iio/common/hid-sensors/*.h
+
+  echo "Installing KConfig files..."
+  find . -name 'Kconfig*' -exec install -Dm644 {} "$builddir/{}" \;
+
+  echo "Removing unneeded architectures..."
+  local arch
+  for arch in "$builddir"/arch/*/; do
+    [[ $arch = */arm64/ ]] && continue
+    echo "Removing $(basename "$arch")"
+    rm -r "$arch"
+  done
+
+  echo "Removing documentation..."
+  rm -r "$builddir/Documentation"
+
+  echo "Removing broken symlinks..."
+  find -L "$builddir" -type l -printf 'Removing %P\n' -delete
+
+  echo "Removing loose objects..."
+  find "$builddir" -type f -name '*.o' -printf 'Removing %P\n' -delete
+
+  echo "Stripping build tools..."
+  local file
+  while read -rd '' file; do
+    case "$(file -Sib "$file")" in
+      application/x-sharedlib\;*)      # Libraries (.so)
+        strip -v $STRIP_SHARED "$file" ;;
+      application/x-archive\;*)        # Libraries (.a)
+        strip -v $STRIP_STATIC "$file" ;;
+      application/x-executable\;*)     # Binaries
+        strip -v $STRIP_BINARIES "$file" ;;
+      application/x-pie-executable\;*) # Relocatable binaries
+        strip -v $STRIP_SHARED "$file" ;;
+    esac
+  done < <(find "$builddir" -type f -perm -u+x ! -name vmlinux -print0)
+
+  echo "Stripping vmlinux..."
+  strip -v $STRIP_STATIC "$builddir/vmlinux"
+
+  echo "Adding symlink..."
+  mkdir -p "$pkgdir/usr/src"
+  ln -sr "$builddir" "$pkgdir/usr/src/$pkgbase"
+}
+
+pkgname=(
+  "$pkgbase"
+  "$pkgbase-headers"
+)
+for _p in "${pkgname[@]}"; do
+  eval "package_$_p() {
+    $(declare -f "_package${_p#$pkgbase}")
+    _package${_p#$pkgbase}
+  }"
+done

notes/phase7-c2-2026-05-08.md

@@ -0,0 +1,63 @@
+# Patch C2 Phase 7 — N=3 ramp results
+
+**Date:** 2026-05-08
+**Module:** `bes2600.ko` srcversion `619A51E61BF5479AAC146E6` (cleanups + F + G + D + E + C2)
+**Rig:** ohm fresh boot, wired enu1 path for control, wlan0 for data probes
+**Stress:** netcat sender, `pv -L 4m`, 30 s per rep
+
+---
+
+## Results table
+
+| rep | uptime (s) | rate (MB/s) |
+|---:|---:|---:|
+| 1 | 544 | **2.289** |
+| 2 | 716 | **2.165** |
+| 3 | 750 | **2.376** |
+
+**N=3:** mean 2.277, median 2.289, min 2.165, max 2.376
+
+## Comparison to baselines
+
+| series | mean MB/s | Δ vs Patch B | Δ vs v3 |
+|---|---:|---:|---:|
+| Patch B (run-20260507-patchC-preflight, N=1) | 1.362 | — | -42% |
+| Patch C v3 N=3 (run-20260507-N3v3-rep*) | 2.352 | +73% | — |
+| Patch C v3 + F + G + D + E + C2 N=3 (this rep set) | 2.277 | +67% | -3% |
+
+Δ vs v3 is **within rep variance** (v3 N=3 had min 2.102, max 2.590 → spread ±20%; this set's spread is similar). Statistically indistinguishable.
+
+## Verdict: no measurable C2 throughput delta
+
+The tasklet hop in `ieee80211_rx_irqsafe` was apparently cheap on this kernel. Migrating 6 sites from `_irqsafe` to `_rx_ni` (synchronous-from-process-context, internal `local_bh_disable` wrap) preserves throughput but doesn't measurably improve it.
+
+**This was a predicted outcome.** The C2 Phase 4 plan §4.5 said:
+> "If <2%, Phase 7 says 'marginal but no regression' and we ship anyway for upstream-cleanliness."
+
+Observed: -3% (within noise) → falls into the "marginal but no regression" bucket. Ship for the kernel.org submission story (no `_irqsafe` from process context = upstream-idiomatic) even though performance is unchanged.
+
+## Receipts checklist
+
+- [x] N=3 reps captured at fresh-chip uptime (544/716/750 s — within first 13 min, before scan-failure-cadence onset)
+- [x] All reps under same conditions: same fresh boot, same nc listener, same AP (newton, BSSID c0:25:06:e6:61:b0 on chan 1)
+- [x] No WARN/BUG/oops on any rep
+- [x] dmesg pattern: only the pre-existing wsm_generic_confirm 0x0007 noise — same on Patch B / Patch F / Patch C v3 / D / E / C2 (firmware-side, independent of all our patches)
+- [x] Wired-rig telemetry collection — would have caught any wedge that wlan0 ate
+- [x] Rig-failure-is-finding: an early "0-throughput" set of reps was rig artifact (nc-loop race, port-binding state from a prior session) — caught and discounted per `feedback_rig_failure_is_finding`. The recovered N=3 reps used setsid-detached listener + post-reboot fresh state.
+
+## Phase 8 lesson
+
+**Drop-in replacements with the right kerneldoc reading still need Phase 7 measurement.** I expected +5-15% from removing the tasklet schedule. Got -3% (noise). The cost we were saving was already amortised by something else (NAPI infra? per-CPU softirq scheduling?). The kerneldoc-correctness story stands; the perf story does not.
+
+**Memory entry:** the perf-vs-correctness distinction is worth keeping. `_irqsafe → _rx_ni` is a CORRECTNESS / API-cleanliness move, not a performance optimization. Don't oversell predicted deltas without baseline measurement.
+
+## Out-of-scope follow-ups
+
+- Patch C v3 architectural win is the durable +73%. C / D / E / C2 / F / G are smaller cleanups that don't compound visibly.
+- Bug #5 RX-degradation campaign already closed (hypothesis falsified).
+- Task #24 (post-cleanup observation of bh.c symptom-shaped artifacts): mostly answered.
+- Task #25 (Allwinner sw_mci_check_r1_ready measurement): can be done during any future stress run; not on critical path.
+
+---
+
+*Phase 7 captured 2026-05-08 by Claude (noether). Patch C2 closes the post-Bug-#5 cleanup track. Throughput ceiling on this hardware = ~2.4 MB/s sustained @ 4 MB/s sender, fresh chip; further improvement would need firmware-side fixes (the wsm_generic_confirm 0x0007 path), not driver-side.*