I don’t mean to read it twice. The solution is to make first read later. I
didn’t modify the original code to make code difference less and simple. I
guess it should work to remove the original read there.
From: Liu, Leo <leo....@amd.com>
Sent: Tuesday, May 28, 2019 12:40 AM
To: Li, Ching-shih (Louis) <ching-shih...@amd.com>; S, Shirish
<shiris...@amd.com>; Grodzovsky, Andrey <andrey.grodzov...@amd.com>; Zhang,
Jerry <jerry.zh...@amd.com>; Deng, Emily <emily.d...@amd.com>; Deucher,
Alexander <alexander.deuc...@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/amdgpu: fix ring test failure issue during s3 in vce
3.0
int amdgpu_vce_ring_test_ring(struct amdgpu_ring *ring)
{
struct amdgpu_device *adev = ring->adev;
uint32_t rptr = amdgpu_ring_get_rptr(ring);
unsigned i;
int r, timeout = adev->usec_timeout;
/* skip ring test for sriov*/
if (amdgpu_sriov_vf(adev))
return 0;
r = amdgpu_ring_alloc(ring, 16);
if (r)
return r;
amdgpu_ring_write(ring, VCE_CMD_END);
amdgpu_ring_commit(ring);
Above is original code, rptr is updated when called, and below is your patch,
my question is why do you need to get rptr twice?
@@ -1084,6 +1084,8 @@ int amdgpu_vce_ring_test_ring(struct amdgpu_ring *ring)
if (r)
return r;
+ rptr = amdgpu_ring_get_rptr(ring);
+
amdgpu_ring_write(ring, VCE_CMD_END);
amdgpu_ring_commit(ring);
On 5/27/19 12:22 PM, Li, Ching-shih (Louis) wrote:
Hi Leo,
Yes, I confirm it is the root cause for the Chrome S3 issue. Whenever system is
resumed, the original instruction always gets zero. However, I have no idea why
it fails, and didn’t verify this problem on CRB or any other Linux platform yet.
Although I think the ideal solution is an indicator, e.g. a register, for
driver to check if related firmware and hardware are ready to work. So driver
can make sure it is ok to read rptr. Without any reference document, I can only
try to solve the problem by modifying driver. Debug traces reveal that only
first rptr read fails, but the read in check loop is ok. Therefore, a solution
comes to mind: to update rptr later for initial rptr value. Tests prove it
working in Chrome platforms. Fyi~
BR,
Louis
From: Liu, Leo <leo....@amd.com><mailto:leo....@amd.com>
Sent: Monday, May 27, 2019 9:01 PM
To: S, Shirish <shiris...@amd.com><mailto:shiris...@amd.com>; Grodzovsky,
Andrey <andrey.grodzov...@amd.com><mailto:andrey.grodzov...@amd.com>; Zhang,
Jerry <jerry.zh...@amd.com><mailto:jerry.zh...@amd.com>; Deng, Emily
<emily.d...@amd.com><mailto:emily.d...@amd.com>; Deucher, Alexander
<alexander.deuc...@amd.com><mailto:alexander.deuc...@amd.com>
Cc: amd-gfx@lists.freedesktop.org<mailto:amd-gfx@lists.freedesktop.org>; Li,
Ching-shih (Louis) <ching-shih...@amd.com><mailto:ching-shih...@amd.com>
Subject: Re: [PATCH] drm/amdgpu: fix ring test failure issue during s3 in vce
3.0
On 5/27/19 3:42 AM, S, Shirish wrote:
From: Louis Li <ching-shih...@amd.com><mailto:ching-shih...@amd.com>
[What]
vce ring test fails consistently during resume in s3 cycle, due to
mismatch read & write pointers.
On debug/analysis its found that rptr to be compared is not being
correctly updated/read, which leads to this failure.
Below is the failure signature:
[drm:amdgpu_vce_ring_test_ring] *ERROR* amdgpu: ring 12 test failed
[drm:amdgpu_device_ip_resume_phase2] *ERROR* resume of IP block <vce_v3_0>
failed -110
[drm:amdgpu_device_resume] *ERROR* amdgpu_device_ip_resume failed (-110).
[How]
fetch rptr appropriately, meaning move its read location further down
in the code flow.
With this patch applied the s3 failure is no more seen for >5k s3 cycles,
which otherwise is pretty consistent.
Signed-off-by: Louis Li <ching-shih...@amd.com><mailto:ching-shih...@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
index c021b11..92f9d46 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
@@ -1084,6 +1084,8 @@ int amdgpu_vce_ring_test_ring(struct amdgpu_ring *ring)
if (r)
return r;
+ rptr = amdgpu_ring_get_rptr(ring);
+
The rptr update is there:
uint32_t rptr = amdgpu_ring_get_rptr(ring);
Are you sure this is the root cause?
Regards,
Leo
amdgpu_ring_write(ring, VCE_CMD_END);
amdgpu_ring_commit(ring);
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