From 2311720a0182756f175fbf4afc1fb76ac487b587 Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Wed, 15 Jun 2022 09:24:35 -0700 Subject: [PATCH] drm/msm: Fix fence rollover issue And while we are at it, let's start the fence counter close to the rollover point so that if issues slip in, they are more obvious. Signed-off-by: Rob Clark Fixes: fde5de6cb461 ("drm/msm: move fence code to it's own file") Fixes: 5f3aee4ceb5b ("drm/msm: Handle fence rollover") Patchwork: https://patchwork.freedesktop.org/patch/489619/ Link: https://lore.kernel.org/r/20220615162435.3011793-1-robdclark@gmail.com [DB: fixed the conflict while applying the patch] Signed-off-by: Dmitry Baryshkov --- drivers/gpu/drm/msm/msm_fence.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/msm_fence.c b/drivers/gpu/drm/msm/msm_fence.c index 38e3323..a47e5837 100644 --- a/drivers/gpu/drm/msm/msm_fence.c +++ b/drivers/gpu/drm/msm/msm_fence.c @@ -28,6 +28,14 @@ msm_fence_context_alloc(struct drm_device *dev, volatile uint32_t *fenceptr, fctx->fenceptr = fenceptr; spin_lock_init(&fctx->spinlock); + /* + * Start out close to the 32b fence rollover point, so we can + * catch bugs with fence comparisons. + */ + fctx->last_fence = 0xffffff00; + fctx->completed_fence = fctx->last_fence; + *fctx->fenceptr = fctx->last_fence; + return fctx; } @@ -52,7 +60,8 @@ void msm_update_fence(struct msm_fence_context *fctx, uint32_t fence) unsigned long flags; spin_lock_irqsave(&fctx->spinlock, flags); - fctx->completed_fence = max(fence, fctx->completed_fence); + if (fence_after(fence, fctx->completed_fence)) + fctx->completed_fence = fence; spin_unlock_irqrestore(&fctx->spinlock, flags); } -- 2.7.4