lkml.org 
[lkml]   [2012]   [Oct]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: 3.5 regression on i915
Date
On Sat, 6 Oct 2012 01:42:18 +0200, Willy Tarreau <w@1wt.eu> wrote:
> Chris, Daniel,
>
> since version 3.5, my Asus EeePC 1005HA bugs during startx. I didn't
> have the time to investigate until this evening.
>
> I could bisect the commits and found that the following one was merged
> in 3.5-rc1 and is responsible for these bugs that can reliably be
> triggered :
>
> 1b50247a8ddde4af5aaa0e6bc125615372ce6c16 is the first bad commit
> commit 1b50247a8ddde4af5aaa0e6bc125615372ce6c16
> Author: Chris Wilson <chris@chris-wilson.co.uk>
> Date: Tue Apr 24 15:47:30 2012 +0100
>
> drm/i915: Remove the list of pinned inactive objects
>
> Simplify object tracking by removing the inactive but pinned list. The
> only place where this was used is for counting the available memory,
> which is just as easy performed by checking all objects on the rare
> occasions it is required (application startup). For ease of debugging,
> we keep the reporting of pinned objects through the error-state and
> debugfs.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>
> I tried to revert it from 3.5.6-rc1 but it does not revert cleanly at all
> and I'm totall unfamiliar with this code to attempt anything sane at this
> time of the night.
>
> The crash happens here in i915_gem_entervt_ioctl() :
>
> 3659 BUG_ON(!list_empty(&dev_priv->mm.active_list));
> 3660 BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
> -> 3661 BUG_ON(!list_empty(&dev_priv->mm.inactive_list));
> 3662 mutex_unlock(&dev->struct_mutex);

That BUG_ON there is silly and can simply be removed. The check is to
verify that no batches were submitted to the kernel whilst the UMS/GEM
client was suspended - to which the BUG_ONs are a crude approximation.
Furthermore, the checks are too late, since it means we attempted to
program the hardware whilst it was in an invalid state, the BUG_ONs are
the least of your concerns at that point.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre


\
 
 \ /
  Last update: 2012-10-06 10:41    [W:0.058 / U:0.868 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site