Hi

Am 12.06.23 um 11:14 schrieb Marijn Suijten:
> On 2023-06-12 06:16:15, Dmitry Baryshkov wrote:
>> Since commit 93e81e38e197 ("drm/fb_helper: Minimize damage-helper
>> overhead") the drm_fb_helper_funcs::fb_dirty helper is required for
>> proper dirty/damage processing. The drm/msm driver requires that to
>> function to let CMD panels to work. Use simplified version of
>> drm_fbdev_generic_helper_fb_dirty() to fix support for CMD mode panels.
>>
>> Reported-by: Degdag Mohamed <degdagmohamed@gmail.com>
>> Fixes: 93e81e38e197 ("drm/fb_helper: Minimize damage-helper overhead")
>> Cc: Thomas Zimmermann <tzimmermann@suse.de>
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> 
> Thanks, this solves the following warning:
> 
>      msm_dpu ae01000.display-controller: drm_WARN_ON_ONCE(!helper->funcs->fb_dirty)
>      WARNING: CPU: 0 PID: 9 at drivers/gpu/drm/drm_fb_helper.c:381 drm_fb_helper_damage_work+0x1c0/0x20c
> 
> Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
> 
> Note that drm_fb_helper_funcs documents this as "This callback is
> optional": is it no longer optional, or are we enabling a damage feature
> that makes it not-optional?

It is optional in the sense that most hardware and drivers don't require 
damage handling. Those that do, also require this callback.

Best regards
Thomas

> 
> - Marijn
> 
>> ---
>>   drivers/gpu/drm/msm/msm_fbdev.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
>> index fa9c1cbffae3..b933a85420f6 100644
>> --- a/drivers/gpu/drm/msm/msm_fbdev.c
>> +++ b/drivers/gpu/drm/msm/msm_fbdev.c
>> @@ -139,8 +139,28 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
>>   	return ret;
>>   }
>>   
>> +static int msm_fbdev_fb_dirty(struct drm_fb_helper *helper,
>> +			      struct drm_clip_rect *clip)
>> +{
>> +	struct drm_device *dev = helper->dev;
>> +	int ret;
>> +
>> +	/* Call damage handlers only if necessary */
>> +	if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
>> +		return 0;
>> +
>> +	if (helper->fb->funcs->dirty) {
>> +		ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
>> +		if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
>> +			return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>   static const struct drm_fb_helper_funcs msm_fb_helper_funcs = {
>>   	.fb_probe = msm_fbdev_create,
>> +	.fb_dirty = msm_fbdev_fb_dirty,
>>   };
>>   
>>   /*
>> -- 
>> 2.39.2
>>

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)