[PATCH] drm/msm: Fix 0xfffflub in "Refactor address space initialization"

From: John Stultz
Date: Sat Jun 13 2020 - 00:24:05 EST


This week I started seeing GPU crashes on my DragonBoard 845c
which I narrowed down to being caused by commit ccac7ce373c1
("drm/msm: Refactor address space initialization").

Looking through the patch, Jordan and I couldn't find anything
obviously wrong, so I ended up breaking that change up into a
number of smaller logical steps so I could figure out which part
was causing the trouble.

Ends up, visually counting 'f's is hard, esp across a number
of lines:
0xfffffff != 0xffffffff

This patch corrects the end value we pass in to
msm_gem_address_space_create() in
adreno_iommu_create_address_space() so that it matches the value
used before the problematic patch landed.

With this change, I no longer see the GPU crashes that were
affecting me.

Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
Cc: Rob Clark <robdclark@xxxxxxxxx>
Cc: Sean Paul <sean@xxxxxxxxxx>
Cc: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
Cc: freedreno@xxxxxxxxxxxxxxxxxxxxx
Fixes: ccac7ce373c1 ("drm/msm: Refactor address space initialization")
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
drivers/gpu/drm/msm/adreno/adreno_gpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index 89673c7ed473..3d4efe684a98 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -194,7 +194,7 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
struct msm_gem_address_space *aspace;

aspace = msm_gem_address_space_create(mmu, "gpu", SZ_16M,
- 0xfffffff);
+ 0xffffffff);

if (IS_ERR(aspace) && !IS_ERR(mmu))
mmu->funcs->destroy(mmu);
--
2.17.1