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Commit 64a17e1d authored by Xiaojie Yuan's avatar Xiaojie Yuan Committed by Greg Kroah-Hartman
Browse files

drm/amdgpu/sdma5: fix wptr overwritten in ->get_wptr() 



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: default avatarLe Ma <le.ma@amd.com>
Signed-off-by: default avatarXiaojie Yuan <xiaojie.yuan@amd.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9f8d3d2f

drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c

+8 −18
Original line number Diff line number Diff line
@@ -286,30 +286,20 @@ static uint64_t sdma_v5_0_ring_get_rptr(struct amdgpu_ring *ring) 
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;

}



/**