From ad64a8fb1911ae26fcb15ad8c7fbb45e66670041 Mon Sep 17 00:00:00 2001
From: Rob Clark <robdclark@chromium.org>
Date: Wed, 15 Jun 2022 09:24:35 -0700
Subject: drm/msm: Fix fence rollover issue
Git-commit: 2311720a0182756f175fbf4afc1fb76ac487b587
Patch-mainline: v6.0-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849
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 <robdclark@chromium.org>
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 <dmitry.baryshkov@linaro.org>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
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 38e3323bc232..a47e5837c528 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);
}
--
2.38.1