Bug 42839
| Summary: | drm/i915: wrong fifo size due to uncareful refactoring which results in an xserver crash at 800x600 | ||
|---|---|---|---|
| Product: | Drivers | Reporter: | Lukas Anzinger (l.anzinger) |
| Component: | Video(DRI - Intel) | Assignee: | drivers_video-dri-intel (drivers_video-dri-intel) |
| Status: | RESOLVED CODE_FIX | ||
| Severity: | normal | CC: | chris, jrnieder |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.33.20 | Subsystem: | |
| Regression: | Yes | Bisected commit-id: | |
| Attachments: | Fix wrong fifo size regression | ||
commit 8f4695ed1c9e068772bcce4cd4ff03f88d57a008 Author: Adam Jackson <ajax@redhat.com> Date: Fri Apr 16 18:20:57 2010 -0400 drm/i915: Attempt to fix watermark setup on 85x (v2) IS_MOBILE() catches 85x, so we'd always try to use the 9xx FIFO sizing; since there's an explicit 85x version, this seems wrong. v2: Handle 830m correctly too. Signed-off-by: Adam Jackson <ajax@redhat.com> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Eric Anholt <eric@anholt.net> Please test that and then send it to stable@kernel.org, adding your Reported-and-tested-by and Bugzilla reference. Hi, looks good to me. I opt for inclusion in the 2.6.33.y branch. Regards, Lukas References: http://bugs.debian.org/661696 |
Created attachment 72498 [details] Fix wrong fifo size regression Hi, I've encountered a nasty bug in the drm/i915 part of Debian's stable kernel. The code is also present in 2.6.33.20, which is the latest stable upstream release of 2.6.33.y at the time of writing. During a refactoring of the i915 driver a regression has been introduced (commit e70236a8d3d0a4c100a0b9f7d394d9bda9c56aca): For some chipsets the wrong fifo size is determined which results in lot's of pixel errors when starting the xserver and choosing 800x600 as a resolution. If another resolution is used (eg. 1024x768 or 1280x1024), I don't encounter this problem. I've attached a patch that fixes the problem (no pixel errors anymore) and determines the correct fifo size. Regards, Lukas