[PATCH 0/1] DRM commit e3c92eb causes OpenChrome DRM to crash during boot

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From: Kevin Brace <kevinbrace@xxxxxxxxxxxxxxxxxxxx>

Hi,

I work on an out of the kernel tree DRM module for VIA Technologies Chrome
integrated graphics (https://cgit.freedesktop.org/openchrome/drm-openchrome/),
and DRM commit e3c92eb4a84fb0f00442e6b5cabf4f11b0eaaf41 (drm/ttm: rework on
ttm_resource to use size_t type) definitely breaks my code.
The bug is 100% reproducible.
It took me about 2 1/2 weeks to track down the bad commit due to the general 
difficulty of debugging DRM code since it gets loaded by the OS way before
sysklogd service is even up and running to record a crash.
For this bug, bug check did not come on, so this made it very hard to track
down the bad commit.
After reversing many commits, I was able to see a difference in the behavior 
of the code if this particular commit was reversed.
I am including a patch that I think correctly fixes the erroneous code, and
OpenChrome DRM works correctly (i.e., OS now boots properly) if the patch is
applied. 
Please be more careful tinkering with TTM in the future since it tends to be
very fragile.

--
Kevin Brace (1):
  drm/ttm: Fix of rework on ttm_resource to use size_t type commit

 drivers/gpu/drm/ttm/ttm_bo_util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.38.2




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