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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
drm/amdgpu/hdp5.2: use memcfg register to post the write for HDP flush
Reading back the remapped HDP flush register seems to cause
problems on some platforms. All we need is a read, so read back
the memcfg register.
Fixes: f756dbac1ce1 ("drm/amdgpu/hdp5.2: do a posting read when flushing HDP")
Reported-by: Alexey Klimov <alexey.klimov@linaro.org>
Link: https://lists.freedesktop.org/archives/amd-gfx/2025-April/123150.html
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4119
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3908
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 4a89b7698e771914b4d5b571600c76e2fdcbe2a9)
Cc: stable@vger.kernel.org
+11
-1
+11
-1
drivers/gpu/drm/amd/amdgpu/hdp_v5_2.c
+11
-1
drivers/gpu/drm/amd/amdgpu/hdp_v5_2.c
···
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if (!ring || !ring->funcs->emit_wreg) {
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WREG32_NO_KIQ((adev->rmmio_remap.reg_offset + KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL) >> 2,
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0);
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-
RREG32_NO_KIQ((adev->rmmio_remap.reg_offset + KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL) >> 2);
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+
if (amdgpu_sriov_vf(adev)) {
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+
/* this is fine because SR_IOV doesn't remap the register */
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+
RREG32_NO_KIQ((adev->rmmio_remap.reg_offset + KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL) >> 2);
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+
} else {
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/* We just need to read back a register to post the write.
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* Reading back the remapped register causes problems on
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* some platforms so just read back the memory size register.
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*/
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+
if (adev->nbio.funcs->get_memsize)
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adev->nbio.funcs->get_memsize(adev);
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+
}
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} else {
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amdgpu_ring_emit_wreg(ring,
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(adev->rmmio_remap.reg_offset + KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL) >> 2,