[PATCH 2/2] drm/amdgpu/mes12: fix queue init wptr reset

[Runyu Xiao]

mes_v12_0_queue_init() resets ring->wptr_cpu_addr with a plain 32-bit
store in the reset/suspend path even though the same carrier is
accessed with atomic64_set()/atomic64_read() and support_64bit_ptrs is
enabled.

This is not just a missing atomic annotation. The MES queue write
pointer is a shared 64-bit carrier, and *ring->wptr_cpu_addr = 0 only
clears the low 32 bits. A later atomic64_read() can then observe stale
high 32 bits instead of a real zeroed reset state.

Use atomic64_set((atomic64_t *)ring->wptr_cpu_addr, 0) so the reset
path updates the full 64-bit wptr with the same access family as the
existing readers and writers.

Build-tested by compiling mes_v12_0.o.

No AMDGPU hardware was available for end-to-end runtime testing.

Fixes: 785f0f9fe742 ("drm/amdgpu: Add mes v12_0 ip block support (v4)")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Runyu Xiao <runyu.xiao@xxxxxxxxxx>
---
 drivers/gpu/drm/amd/amdgpu/mes_v12_0.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c b/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
index 023c7345e..22ed7bb51 100644
--- a/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
@@ -1476,7 +1476,7 @@ static int mes_v12_0_queue_init(struct amdgpu_device *adev,
 
 	if ((adev->enable_uni_mes || pipe == AMDGPU_MES_SCHED_PIPE) &&
 	    (amdgpu_in_reset(adev) || adev->in_suspend)) {
-		*(ring->wptr_cpu_addr) = 0;
+		atomic64_set((atomic64_t *)ring->wptr_cpu_addr, 0);
 		*(ring->rptr_cpu_addr) = 0;
 		amdgpu_ring_clear_ring(ring);
 	}
-- 
2.34.1