Re: [PATCH 1/8] display: fix blend_mode for non-overlay planes

[Alex Hung <alex.hung@amd.com>]

This looks like a fix for the same problem Melissa tried to address in

https://lore.kernel.org/amd-gfx/DS0PR12MB65342AEDED0D035DFA92E4189CA32@DS0PR12MB6534.namprd12.prod.outlook.com/T/#mf6847a9e8d013adae40afa3c2ca0c64ebd3fcb50

Please advise if it is for a different issue.

Thanks.

On 8/21/26 13:42, Bert Karwatzki wrote:
> Am Freitag, dem 21.08.2026 um 14:47 -0400 schrieb Joshua Peisach:
>> On Fri Aug 14, 2026 at 11:17 AM EDT, Bert Karwatzki wrote:
>>> Previously drm_plane_create_blend_mode_property() was only called for
>>> planes of type DRM_PLANE_TYPE_OVERLAY. Since commit commit 860e748bddcc
>>> ("drm: ensure blend mode supported if pixel format with alpha exposed")
>>> this results in warnings from validate_blend_mode_for_alpha_formats().
>>> We fix this here by calling drm_plane_create_blend_mode_property() for
>>> all plane types if the plane is supporting a format with
>>> per_pixel_alpha.
>>>
>>> Signed-off-by: Bert Karwatzki <spasswolf@web.de>
>>> ---
>>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c  | 5 ++++-
>>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c | 3 +--
>>>   2 files changed, 5 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
>>> index 62eac6e65334..a6a54351ea56 100644
>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
>>> @@ -755,13 +755,16 @@ int amdgpu_dm_crtc_init(struct amdgpu_display_manager *dm,
>>>   	struct drm_plane *cursor_plane;
>>>   	bool has_degamma;
>>>   	int res = -ENOMEM;
>>> +	struct dc_plane_cap dummy_cap = {
>>> +		.per_pixel_alpha = 1,
>>> +	};
>>>   
>>>   	cursor_plane = kzalloc_obj(*cursor_plane);
>>>   	if (!cursor_plane)
>>>   		goto fail;
>>>   
>>>   	cursor_plane->type = DRM_PLANE_TYPE_CURSOR;
>>> -	res = amdgpu_dm_plane_init(dm, cursor_plane, 0, NULL);
>>> +	res = amdgpu_dm_plane_init(dm, cursor_plane, 0, &dummy_cap);
>>>   
>>>   	acrtc = kzalloc_obj(struct amdgpu_crtc);
>>>   	if (!acrtc)
>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
>>> index 824ef3ce5de0..4c0c6a8a0dac 100644
>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
>>> @@ -2208,8 +2208,7 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm,
>>>   	if (res)
>>>   		return res;
>>>   
>>> -	if (plane->type == DRM_PLANE_TYPE_OVERLAY &&
>>> -	    plane_cap && plane_cap->per_pixel_alpha) {
>>> +	if (plane_cap && plane_cap->per_pixel_alpha) {
>>>   		unsigned int blend_caps = BIT(DRM_MODE_BLEND_PIXEL_NONE) |
>>>   					  BIT(DRM_MODE_BLEND_PREMULTI) |
>>>   					  BIT(DRM_MODE_BLEND_COVERAGE);
>>
>> Not sure where the full patch set is, but this does make the warning
>> go away.
>>
>> Tested-by: Joshua Peisach <jpeisach@ubuntu.com>
> 
> This is actually the only patch, the 1/8 is an artifact from using
> git format-patch which I forgot to remove.
> 
> Bert Karwatzki