From: Dmitry Baryshkov dmitry.baryshkov@linaro.org
[ Upstream commit b4fb748f0b734ce1d2e7834998cc599fcbd25d67 ]
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: b1fc2839d2f9 ("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.or... Signed-off-by: Rob Clark robdclark@chromium.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c index 8abc9a2b114a2..6e326d851ba53 100644 --- a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c +++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c @@ -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)