Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/amdgpu/hdp7: 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: 689275140cb8 ("drm/amdgpu/hdp7.0: 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>
+6
-1
+6
-1
drivers/gpu/drm/amd/amdgpu/hdp_v7_0.c
+6
-1
drivers/gpu/drm/amd/amdgpu/hdp_v7_0.c
···
32
32
{
33
33
if (!ring || !ring->funcs->emit_wreg) {
34
34
WREG32((adev->rmmio_remap.reg_offset + KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL) >> 2, 0);
35
-
RREG32((adev->rmmio_remap.reg_offset + KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL) >> 2);
35
+
/* We just need to read back a register to post the write.
36
+
* Reading back the remapped register causes problems on
37
+
* some platforms so just read back the memory size register.
38
+
*/
39
+
if (adev->nbio.funcs->get_memsize)
40
+
adev->nbio.funcs->get_memsize(adev);
36
41
} else {
37
42
amdgpu_ring_emit_wreg(ring, (adev->rmmio_remap.reg_offset + KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL) >> 2, 0);
38
43
}