besser/danctnix-besser-pkgbuild/README.md

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.

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⚠️ 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'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This directory remains for historical reference (pkgrel=1..3 hand-managed flow + per-patch design notes that haven't been ported to the new home yet).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 and marfrit-packages PR #28 for the migration.

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TL;DR

Current package	linux-pinetab2-danctnix-besser-7.0.danctnix1-5-aarch64.pkg.tar.zst (built via 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 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, 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 lockdep fix (pending_record_lock SOFTIRQ-safe → -unsafe inversion). 4-patch cumulative, 162 704 B, b2sum 0eb091ddaba4…. Closes besser#18 + besser#1.

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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 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)	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.

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:

cd ~/src/marfrit-packages/arch/linux-pinetab2-danctnix-besser
makepkg -s

To refresh the cumulative patch from a new kernel-agent manifest state:

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)

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 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:

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:

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:

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:

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:

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.

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).