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iter2 Fix 1: invalidate format cache on DestroyContext + REQBUFS(0) on CAPTURE in resolution-change path

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Fix 1 of iteration 2 per phase4_iter2_plan.md.

Adds surface_reset_format_cache() exposed from src/surface.h. Called
from RequestDestroyContext after the dual REQBUFS(0). Without this,
multi-video Firefox sessions on mozilla.org corrupted the next
session's CAPTURE format query: the kernel reset to defaults but
our LAST_OUTPUT_WIDTH/HEIGHT cache still said 'already 1920x1088,'
so the next G_FMT returned 48x48 and the exported descriptor
encoded wrong pitch/offset.

Also adds REQBUFS(0) on CAPTURE in the resolution-change path of
RequestCreateSurfaces2 (Sonnet Phase 5 review iter2 9.1). The
existing code only did REQBUFS(0) on OUTPUT before re-S_FMTting;
hantro derives CAPTURE format from OUTPUT format, so leftover
CAPTURE buffers from the prior resolution would also block the
implicit format change. Pre-existing bug surfaced by Sonnet's
audit; Fix 3 pool refactor would have exposed it more often.

Limitation noted in surface.h docblock: the LAST_OUTPUT_WIDTH/
HEIGHT cache is a static process-global, so concurrent multi-
context use still races (Sonnet 7.3 / 9.6). Iteration 2 only
addresses sequential sessions. Multi-context safety is iteration 3+.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Markus Fritsche
2026-05-04 19:11:03 +00:00
parent c036a44f98
commit 06beef6248
3 changed files with 50 additions and 4 deletions
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src/surface.c
+18 -4
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@@ -69,6 +69,12 @@
static unsigned int LAST_OUTPUT_WIDTH = 0;
static unsigned int LAST_OUTPUT_HEIGHT = 0;
void surface_reset_format_cache(void)
{
LAST_OUTPUT_WIDTH = 0;
LAST_OUTPUT_HEIGHT = 0;
}
VAStatus RequestCreateSurfaces2(VADriverContextP context, unsigned int format,
unsigned int width, unsigned int height,
VASurfaceID *surfaces_ids,
@@ -114,13 +120,21 @@ VAStatus RequestCreateSurfaces2(VADriverContextP context, unsigned int format,
if (LAST_OUTPUT_WIDTH != width || LAST_OUTPUT_HEIGHT != height) {
/*
* If we've previously allocated OUTPUT buffers at a different
* resolution, tear them down before re-setting the format —
* S_FMT is rejected by V4L2 while buffers exist.
* If we've previously allocated buffers at a different
* resolution, tear them down on BOTH queues before re-setting
* the OUTPUT format. S_FMT is rejected by V4L2 while buffers
* exist; hantro derives CAPTURE format from OUTPUT format, so
* leftover CAPTURE buffers from the prior resolution would
* also block the implicit format change. Sonnet Phase 5
* review (iter2 9.1) flagged this as a missing REQBUFS(0)
* gap on the CAPTURE side of the resolution-change path.
*/
if (LAST_OUTPUT_WIDTH != 0)
if (LAST_OUTPUT_WIDTH != 0) {
(void)v4l2_request_buffers(driver_data->video_fd,
output_type, 0);
(void)v4l2_request_buffers(driver_data->video_fd,
v4l2_type_video_capture(true), 0);
}
rc = v4l2_set_format(driver_data->video_fd, output_type, pixelformat,
width, height);