linux-kernel - Re: [Freedreno] [PATCH RFC v6 07/10] drm/atomic: Loosen FB atomic checks

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Message-ID: <752176d8-23f4-4689-8bf4-db27f153fd39@quicinc.com>
Date:   Fri, 22 Sep 2023 10:49:23 -0700
From:   Jessica Zhang <quic_jesszhan@...cinc.com>
To:     Pekka Paalanen <ppaalanen@...il.com>
CC:     <linux-arm-msm@...r.kernel.org>, <freedreno@...ts.freedesktop.org>,
        <sebastian.wick@...hat.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        "Sean Paul" <sean@...rly.run>, <dri-devel@...ts.freedesktop.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        <quic_abhinavk@...cinc.com>, "Maxime Ripard" <mripard@...nel.org>,
        <linux-kernel@...r.kernel.org>, Rob Clark <robdclark@...il.com>,
        <laurent.pinchart@...asonboard.com>,
        Daniel Vetter <daniel@...ll.ch>, <contact@...rsion.fr>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        <wayland-devel@...ts.freedesktop.org>,
        "David Airlie" <airlied@...il.com>, <ville.syrjala@...ux.intel.com>
Subject: Re: [Freedreno] [PATCH RFC v6 07/10] drm/atomic: Loosen FB atomic
 checks



On 8/29/2023 1:22 AM, Pekka Paalanen wrote:
> On Mon, 28 Aug 2023 17:05:13 -0700
> Jessica Zhang <quic_jesszhan@...cinc.com> wrote:
> 
>> Loosen the requirements for atomic and legacy commit so that, in cases
>> where pixel_source != FB, the commit can still go through.
>>
>> This includes adding framebuffer NULL checks in other areas to account for
>> FB being NULL when non-FB pixel sources are enabled.
>>
>> To disable a plane, the pixel_source must be NONE or the FB must be NULL
>> if pixel_source == FB.
>>
>> Signed-off-by: Jessica Zhang <quic_jesszhan@...cinc.com>
>> ---
>>   drivers/gpu/drm/drm_atomic.c        | 20 +++++++++++---------
>>   drivers/gpu/drm/drm_atomic_helper.c | 36 ++++++++++++++++++++----------------
>>   include/drm/drm_atomic_helper.h     |  4 ++--
>>   include/drm/drm_plane.h             | 29 +++++++++++++++++++++++++++++
>>   4 files changed, 62 insertions(+), 27 deletions(-)
> 
> ...
> 
>> diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
>> index a58f84b6bd5e..4c5b7bcdb25c 100644
>> --- a/include/drm/drm_plane.h
>> +++ b/include/drm/drm_plane.h
>> @@ -992,6 +992,35 @@ static inline struct drm_plane *drm_plane_find(struct drm_device *dev,
>>   #define drm_for_each_plane(plane, dev) \
>>   	list_for_each_entry(plane, &(dev)->mode_config.plane_list, head)
>>   
>> +/**
>> + * drm_plane_solid_fill_enabled - Check if solid fill is enabled on plane
>> + * @state: plane state
>> + *
>> + * Returns:
>> + * Whether the plane has been assigned a solid_fill_blob
>> + */
>> +static inline bool drm_plane_solid_fill_enabled(struct drm_plane_state *state)
>> +{
>> +	if (!state)
>> +		return false;
>> +	return state->pixel_source == DRM_PLANE_PIXEL_SOURCE_SOLID_FILL && state->solid_fill_blob;
>> +}
>> +
>> +static inline bool drm_plane_has_visible_data(const struct drm_plane_state *state)
>> +{
>> +	switch (state->pixel_source) {
>> +	case DRM_PLANE_PIXEL_SOURCE_NONE:
>> +		return false;
>> +	case DRM_PLANE_PIXEL_SOURCE_SOLID_FILL:
>> +		return state->solid_fill_blob != NULL;
> 
> This reminds me, new UAPI docs did not say what the requirements are for
> choosing solid fill pixel source. Is the atomic commit rejected if
> pixel source is solid fill, but solid_fill property has no blob?

Hi Pekka,

Yes, if pixel_source is solid_fill and the solid_fill property blob 
isn't set, the atomic commit should throw an error.

Will document this in the UAPI.

Thanks,

Jessica Zhang

> 
> This should be doc'd.
> 
> 
> Thanks,
> pq
> 
>> +	case DRM_PLANE_PIXEL_SOURCE_FB:
>> +	default:
>> +		WARN_ON(state->pixel_source != DRM_PLANE_PIXEL_SOURCE_FB);
>> +	}
>> +
>> +	return state->fb != NULL;
>> +}
>> +
>>   bool drm_any_plane_has_format(struct drm_device *dev,
>>   			      u32 format, u64 modifier);
>>   
>>
>