[PATCH] drm/amdgpu: disable UVD/VCE for some polaris 12 variants

[Alex Deucher]

On Tue, Nov 27, 2018 at 4:56 AM Christian König
<ckoenig.leichtzumerken at gmail.com> wrote:
>
> Am 27.11.18 um 02:47 schrieb Zhang, Jerry(Junwei):
>
> On 11/26/18 5:28 PM, Christian König wrote:
>
> Am 26.11.18 um 03:38 schrieb Zhang, Jerry(Junwei):
>
> On 11/24/18 3:32 AM, Deucher, Alexander wrote:
>
> Is this required?  Are the harvesting fuses incorrect?  If the blocks are harvested, we should bail out of the blocks properly during init.  Also, please make this more explicit if we still need it.  E.g.,
>
>
>
> The harvest fuse is indeed disabling UVD and VCE, as it's a mining card.
> Then any command to UVD/VCE causing NULL pointer issue, like amdgpu_test.
>
>
> In this case we should fix the NULL pointer issue instead. Do you have a backtrace for this?
>
>
> Sorry to miss the detail.
> The NULL pointer is caused by UVD is not initialized as it's disabled in VBIOS for this kind of card.
>
>
> Yeah, but that should be handled correctly.
>
>
> When cs submit, it will check ring->funcs->parse_cs in amdgpu_cs_ib_fill().
> However, uvd_v6_0_early_init() skip the set ring function, as CC_HARVEST_FUSES is set UVD/VCE disabled.
> Then the access to UVD/VCE ring's funcs will cause NULL pointer issue.
>
> BTW, Windows driver disables UVD/VCE for it as well.
>
>
> You are approaching this from the wrong side. The fact that UVD/VCE is disabled should already be handled correctly.
>
> The problem is rather that in a couple of places (amdgpu_ctx_init for example) we assume that we have at least one UVD/VCE ring.
>
> Alex is right that checking the fuses should be sufficient and we rather need to fix the handling here instead of adding another workaround.

Exactly.  There are already cards out there with no UVD or VCE, so we
need to fix this if it's a problem.  It sounds like userspace is
submitting work to the VCE or UVD rings without checking whether or
not the device supports them in the first place.  We should do a
better job of guarding against that in the kernel.

Alex

>
> Regards,
> Christian.
>
>
> Regards,
> Jerry
>
>
> Regards,
> Christian.
>
>
> AFAIW, windows also disable UVD and VCE in initialization.
>
>        if ((adev->pdev->device == 0x67df) &&
>               (adev->pdev->revision == 0xf7)) {
>
>         /* Some polaris12 variants don't support UVD/VCE */
>
>       } else  {
>
>                  amdgpu_device_ip_block_add(adev, &uvd_v6_3_ip_block);
>
>                  amdgpu_device_ip_block_add(adev, &vce_v3_4_ip_block);
>
>     }
>
>
>
> OK, will explicit the process.
>
> Regards,
> Jerry
>
> That way if we re-arrange the order later, it will be easier to track.
>
>
> Alex
>
> ________________________________
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of Junwei Zhang <Jerry.Zhang at amd.com>
> Sent: Friday, November 23, 2018 3:32:27 AM
> To: amd-gfx at lists.freedesktop.org
> Cc: Zhang, Jerry
> Subject: [PATCH] drm/amdgpu: disable UVD/VCE for some polaris 12 variants
>
> Some variants don't support UVD and VCE.
>
> Signed-off-by: Junwei Zhang <Jerry.Zhang at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/vi.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/vi.c b/drivers/gpu/drm/amd/amdgpu/vi.c
> index f3a4cf1f013a..3338b013ded4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/vi.c
> +++ b/drivers/gpu/drm/amd/amdgpu/vi.c
> @@ -1660,6 +1660,10 @@ int vi_set_ip_blocks(struct amdgpu_device *adev)
>                          amdgpu_device_ip_block_add(adev, &dce_v11_2_ip_block);
>                  amdgpu_device_ip_block_add(adev, &gfx_v8_0_ip_block);
>                  amdgpu_device_ip_block_add(adev, &sdma_v3_1_ip_block);
> +               /* Some polaris12 variants don't support UVD/VCE */
> +               if ((adev->pdev->device == 0x67df) &&
> +                     (adev->pdev->revision == 0xf7))
> +                       break;
>                  amdgpu_device_ip_block_add(adev, &uvd_v6_3_ip_block);
>                  amdgpu_device_ip_block_add(adev, &vce_v3_4_ip_block);
>                  break;
> --
> 2.17.1
>
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