From: Xiaojie Yuan xiaojie.yuan@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.ma@amd.com Signed-off-by: Xiaojie Yuan xiaojie.yuan@amd.com Reviewed-by: Christian König christian.koenig@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@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; }
/**