From: Xiaojie Yuan <xiaojie.y...@amd.com>
commit 05051496b2622e4d12e2036b35165969aa502f89 upstream.
"u64 *wptr" points to the the wptr value in write back buffer and
"*wptr = (*wptr) >> 2;" results in the value being overwritten each time
when ->get_wptr() is called.
umr uses /sys/kernel/debug/dri/0/amdgpu_ring_sdma0 to get rptr/wptr and
decode ring content and it is affected by this issue.
fix and simplify the logic similar as sdma_v4_0_ring_get_wptr().
v2: fix for sdma5.2 as well
v3: drop sdma 5.2 changes for 5.8 and stable
Suggested-by: Le Ma <le...@amd.com>
Signed-off-by: Xiaojie Yuan <xiaojie.y...@amd.com>
Reviewed-by: Christian König <christian.koe...@amd.com>
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
Cc: sta...@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c | 26 ++++++++------------------
1 file changed, 8 insertions(+), 18 deletions(-)
--- a/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c
@@ -286,30 +286,20 @@ static uint64_t sdma_v5_0_ring_get_rptr(
static uint64_t sdma_v5_0_ring_get_wptr(struct amdgpu_ring *ring)
{
struct amdgpu_device *adev = ring->adev;
- u64 *wptr = NULL;
- uint64_t local_wptr = 0;
+ u64 wptr;
if (ring->use_doorbell) {
/* XXX check if swapping is necessary on BE */
- wptr = ((u64 *)&adev->wb.wb[ring->wptr_offs]);
- DRM_DEBUG("wptr/doorbell before shift == 0x%016llx\n", *wptr);
- *wptr = (*wptr) >> 2;
- DRM_DEBUG("wptr/doorbell after shift == 0x%016llx\n", *wptr);
+ wptr = READ_ONCE(*((u64 *)&adev->wb.wb[ring->wptr_offs]));
+ DRM_DEBUG("wptr/doorbell before shift == 0x%016llx\n", wptr);
} else {
- u32 lowbit, highbit;
-
- wptr = &local_wptr;
- lowbit = RREG32(sdma_v5_0_get_reg_offset(adev, ring->me,
mmSDMA0_GFX_RB_WPTR)) >> 2;
- highbit = RREG32(sdma_v5_0_get_reg_offset(adev, ring->me,
mmSDMA0_GFX_RB_WPTR_HI)) >> 2;
-
- DRM_DEBUG("wptr [%i]high== 0x%08x low==0x%08x\n",
- ring->me, highbit, lowbit);
- *wptr = highbit;
- *wptr = (*wptr) << 32;
- *wptr |= lowbit;
+ wptr = RREG32(sdma_v5_0_get_reg_offset(adev, ring->me,
mmSDMA0_GFX_RB_WPTR_HI));
+ wptr = wptr << 32;
+ wptr |= RREG32(sdma_v5_0_get_reg_offset(adev, ring->me,
mmSDMA0_GFX_RB_WPTR));
+ DRM_DEBUG("wptr before shift [%i] wptr == 0x%016llx\n",
ring->me, wptr);
}
- return *wptr;
+ return wptr >> 2;
}
/**
