[PATCH] drm/amd/display: Align num_crtc to max_streams

[Hamza Mahfooz]

On 2/6/23 23:05, Tianci Yin wrote:
> From: tiancyin <tianci.yin at amd.com>
> 
> [Why]
> Display pipe might be harvested on some SKUs, that cause the
> adev->mode_info.num_crtc mismatch with the usable crtc number,
> then below error dmesgs observed after GPU recover.
> 
>    *ERROR* amdgpu_dm_set_crtc_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_crtc_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_crtc_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_pflip_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_pflip_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_pflip_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_pflip_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_vupdate_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_vupdate_irq_state: crtc is NULL at id :3
>    *ERROR* amdgpu_dm_set_vupdate_irq_state: crtc is NULL at id :3
> 
> [How]
> The max_streams is limited number after pipe fuse, align num_crtc
> to max_streams to eliminate the error logs.
> 
> Signed-off-by: tiancyin <tianci.yin at amd.com>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index b31cfda30ff9..87ec2574cc09 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -4285,6 +4285,9 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
>   		break;
>   	}
>   
> +	/* Adjust the crtc number according to the DCN pipe fuse. */
> +	adev->mode_info.num_crtc = dm->dc->caps.max_streams;

This would introduce array-out-bounds issues, since there are arrays of
size AMDGPU_MAX_CRTCS that use num_crtc as a bounds check.

> +
>   	for (i = 0; i < dm->dc->caps.max_streams; i++)
>   		if (amdgpu_dm_crtc_init(dm, mode_info->planes[i], i)) {
>   			DRM_ERROR("KMS: Failed to initialize crtc\n");

-- 
Hamza