[PATCH 9/9] drm/msm/dpu: sync mode_config limits to the FB limits in dpu_plane.c

[Abhinav Kumar]

On 4/19/2024 8:06 PM, Dmitry Baryshkov wrote:
> On Sat, 20 Apr 2024 at 06:05, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>>
>>
>>
>> On 3/19/2024 6:22 AM, Dmitry Baryshkov wrote:
>>> Lift mode_config limits set by the DPU driver to the actual FB limits as
>>> handled by the dpu_plane.c.
>>>
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>>> ---
>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 9 ++-------
>>>    1 file changed, 2 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>> index 7257ac4020d8..e7dda9eca466 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>> @@ -1136,13 +1136,8 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
>>>        dev->mode_config.min_width = 0;
>>>        dev->mode_config.min_height = 0;
>>>
>>> -     /*
>>> -      * max crtc width is equal to the max mixer width * 2 and max height is
>>> -      * is 4K
>>> -      */
>>> -     dev->mode_config.max_width =
>>> -                     dpu_kms->catalog->caps->max_mixer_width * 2;
>>> -     dev->mode_config.max_height = 4096;
>>> +     dev->mode_config.max_width = DPU_MAX_IMG_WIDTH;
>>> +     dev->mode_config.max_height = DPU_MAX_IMG_HEIGHT;
>>>
>>
>> Can you please explain a little more about why the previous limits did
>> not work in the multi-monitor case?
>>
>> We support at the most using 2 LMs per display today. Quad pipe support
>> is not there yet. So by bounding to 2 * mixer_width should have been
>> same as rejecting the mixer width in atomic_check.
> 
> This is the framebuffer limit, not a CRTC size limit.
> 

As discussed on IRC, the DRM fwk uses this to limit the modes on the 
connector, please check

2922 	if (out_resp->count_modes == 0) {
2923 		if (is_current_master)
2924 			connector->funcs->fill_modes(connector,
2925 						     dev->mode_config.max_width,
2926 						     dev->mode_config.max_height);
2927 		else
2928 			drm_dbg_kms(dev, "User-space requested a forced probe on 
[CONNECTOR:%d:%s] but is not the DRM master, demoting to read-only probe",
2929 				    connector->base.id, connector->name);
2930 	}

So the documentation of this doesnt really align with the usage.

Unless we alter these pieces, I am hesitant to ack this.

>>
>>>        dev->max_vblank_count = 0xffffffff;
>>>        /* Disable vblank irqs aggressively for power-saving */
>>>
> 
> 
>