Re: [PATCH 6.1.y] drm/amd/display: Stop amdgpu_dm initialize when link nums greater than max_links

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: cf8b16857db702ceb8d52f9219a4613363e2b1cf

WARNING: Author mismatch between patch and upstream commit:
Backport author: <jianqi.ren.cn@windriver.com>
Commit author: Hersen Wu<hersenxs.wu@amd.com>

Status in newer kernel trees:
6.14.y | Present (exact SHA1)
6.13.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Not found

Note: The patch differs from the upstream commit:
---
1:  cf8b16857db70 ! 1:  97a1c1318e997 drm/amd/display: Stop amdgpu_dm initialize when link nums greater than max_links
    @@ Metadata
      ## Commit message ##
         drm/amd/display: Stop amdgpu_dm initialize when link nums greater than max_links
     
    +    [ Upstream commit cf8b16857db702ceb8d52f9219a4613363e2b1cf ]
    +
         [Why]
         Coverity report OVERRUN warning. There are
         only max_links elements within dc->links. link
    @@ Commit message
         Signed-off-by: Hersen Wu <hersenxs.wu@amd.com>
         Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
         Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
    +    [Minor conflict resolved due to code context change. And the macro MAX_LINKS
    +     is introduced by Commit 60df5628144b ("drm/amd/display: handle invalid
    +     connector indices") after 6.10. So here we still use the original array
    +     length MAX_PIPES * 2]
    +    Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
    +    Signed-off-by: He Zhe <zhe.he@windriver.com>
     
      ## drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c ##
     @@ drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c: static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
      		}
      	}
      
    -+	if (link_cnt > MAX_LINKS) {
    ++	if (link_cnt > (MAX_PIPES * 2)) {
     +		DRM_ERROR(
     +			"KMS: Cannot support more than %d display indexes\n",
    -+				MAX_LINKS);
    ++				MAX_PIPES * 2);
     +		goto fail;
     +	}
     +
    @@ drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c: static int amdgpu_dm_initiali
     -			continue;
     -		}
     -
    - 		link = dc_get_link_at_index(dm->dc, i);
    - 
    - 		if (link->connector_signal == SIGNAL_TYPE_VIRTUAL) {
    + 		aconnector = kzalloc(sizeof(*aconnector), GFP_KERNEL);
    + 		if (!aconnector)
    + 			goto fail;
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |