Re: [PATCH v4 1/2] drm: Introduce drm_crtc_vblank_prepare()

[Mario Limonciello <superm1@kernel.org>]

On 1/29/26 10:40 AM, Leo Li wrote:
> 
> 
> On 2026-01-29 10:15, Leo Li wrote:
>>
>>
>> On 2026-01-28 23:43, Derek John Clark wrote:
>>>> From: Leo Li <sunpeng.li@amd.com>
>>>>
>>>> Some drivers need to perform sleepable operations prior to enabling
>>>> vblank interrupts. A display hardware spin-up from a low-power state
>>>> that requires synchronization with the rest of the driver, for example.
>>>>
>>>> To support this, introduce a DRM-internal drm_crtc_vblank_prepare()
>>>> helper that calls back into the driver -- if implemented -- for DRM to
>>>> do such preparation work before enabling vblank.
>>>>
>>>> v3:
>>>> * Unexport drm_crtc_vblank_prepare() and make it DRM internal
>>>> * Drop warnings in drm core for vblank_prepare(), drivers can do so in
>>>>   their implementations
>>>> * Drop unnecessary crtc null checks
>>>> * Check for drm_dev_has_vblank()
>>>> * Rebase on latest drm-misc-next
>>>>
>>>> v4:
>>>> * EXPORT function to fix build error on DRM_KMS_HELPER=m
>>>>
>>>> Signed-off-by: Leo Li <sunpeng.li@amd.com>
>>>
>>> Hi Leo.
>>>
>>> I wanted to know what branch this series applies to. I'm trying to
>>> troubleshoot a possible vblank issue on the Legion Go 2 and was
>>> pointed towards this patch series. Unfortunately I can't get it to
>>> apply cleanly to drm/drm-fixes, drm/drm-next or stable/linux-6.18.y
>>
>> Hi Derek,
>>
>> This applies to drm-misc-next, here:
>> https://gitlab.freedesktop.org/drm/misc/kernel/-/tree/drm-misc-next
>>
>> Thanks,
>> Leo
> 
> FYI, in case you run into the same issue, I had to blacklist my wifi driver:
> modprobe.blacklist=mt7925e in my kernel cmdline for drm-misc-next to boot.
> 

And if you need wifi while testing there's some fixes for this in 6.19 
that could potentially be cherry picked.

> -Leo
> 
>>
>>>
>>>
>>>  From commit 15392f76405ecb953216b437bed76ffa49cefb7b (HEAD,
>>> drm/drm-next, drm/HEAD):
>>> $ b4 shazam https://lore.kernel.org/dri-devel/20260127194143.176248-1-sunpeng.li@amd.com/
>>> Grabbing thread from
>>> lore.kernel.org/all/20260127194143.176248-1-sunpeng.li@amd.com/t.mbox.gz
>>> Checking for newer revisions
>>> Grabbing search results from lore.kernel.org
>>> Analyzing 2 messages in the thread
>>> Analyzing 0 code-review messages
>>> Checking attestation on all messages, may take a moment...
>>> ---
>>>    [PATCH v4 1/2] drm: Introduce drm_crtc_vblank_prepare()
>>>    [PATCH v4 2/2] drm/amd/display: Implement prepare_vblank_enable callback
>>>    ---
>>>    NOTE: install dkimpy for DKIM signature verification
>>> ---
>>> Total patches: 2
>>> ---
>>> Applying: drm: Introduce drm_crtc_vblank_prepare()
>>> Applying: drm/amd/display: Implement prepare_vblank_enable callback
>>> Patch failed at 0002 drm/amd/display: Implement prepare_vblank_enable callback
>>> error: patch failed: drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c:277
>>> error: drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c: patch
>>> does not apply
>>>
>>>
>>> Thanks,
>>> Derek
>>
>