drm/msm/a5xx: fix the emptyness check in the preempt code

Quoting Yassine: ring->memptrs->rptr is never updated and stays 0, so
the comparison always evaluates to false and get_next_ring always
returns ring 0 thinking it isn't empty.

Fix this by calling get_rptr() instead of reading rptr directly.

Reported-by: Yassine Oudjana <y.oudjana@protonmail.com>
Fixes: b1fc2839d2 ("drm/msm: Implement preemption for A5XX targets")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/522642/
Link: https://lore.kernel.org/r/20230214020956.164473-4-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>
This commit is contained in:
Dmitry Baryshkov 2023-02-14 05:09:55 +03:00 committed by Rob Clark
parent 141f66ebbf
commit b4fb748f0b

View file

@ -63,7 +63,7 @@ static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
struct msm_ringbuffer *ring = gpu->rb[i];
spin_lock_irqsave(&ring->preempt_lock, flags);
empty = (get_wptr(ring) == ring->memptrs->rptr);
empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
spin_unlock_irqrestore(&ring->preempt_lock, flags);
if (!empty)