[PATCH] drm/plane-helper: Add a drm_plane_helper_atomic_check() helper

Thomas Zimmermann tzimmermann at suse.de
Mon Sep 12 11:05:45 UTC 2022


Hi

Am 12.09.22 um 12:40 schrieb Ville Syrjälä:
> On Mon, Sep 12, 2022 at 12:15:22PM +0200, Javier Martinez Canillas wrote:
>> Provides a default plane state check handler for primary planes that are a
>> fullscreen scanout buffer and whose state scale and position can't change.
>>
>> There are some drivers that duplicate this logic in their helpers, such as
>> simpledrm and ssd130x. Factor out this common code into a plane helper and
>> make drivers use it.
>>
>> Suggested-by: Thomas Zimmermann <tzimmermann at suse.de>
>> Signed-off-by: Javier Martinez Canillas <javierm at redhat.com>
>> ---
>>
>>   drivers/gpu/drm/drm_plane_helper.c | 29 +++++++++++++++++++++++++++++
>>   drivers/gpu/drm/solomon/ssd130x.c  | 18 +-----------------
>>   drivers/gpu/drm/tiny/simpledrm.c   | 25 +------------------------
>>   include/drm/drm_plane_helper.h     |  2 ++
>>   4 files changed, 33 insertions(+), 41 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
>> index c7785967f5bf..fb41eee74693 100644
>> --- a/drivers/gpu/drm/drm_plane_helper.c
>> +++ b/drivers/gpu/drm/drm_plane_helper.c
>> @@ -278,3 +278,32 @@ void drm_plane_helper_destroy(struct drm_plane *plane)
>>   	kfree(plane);
>>   }
>>   EXPORT_SYMBOL(drm_plane_helper_destroy);
>> +
>> +/**
>> + * drm_plane_helper_atomic_check() - Helper to check primary planes states
>> + * @plane: plane to check
>> + * @new_state: plane state to check
> 
> That is not a plane state. Also should s/new_// since it's just
> the overall atomic state thing rather than some new or old state.

Using only 'state' is non-intuitive and has lead to bugs where sub-state 
was retrieved from the wrong state information. So we've been using 
'new_state' and 'old_state' explicitly in several places now.

Best regards
Thomas

> 
>> + *
>> + * Provides a default plane state check handler for primary planes whose atomic
>> + * state scale and position is not expected to change because the primary plane
>> + * is always a fullscreen scanout buffer.
>> + *
>> + * RETURNS:
>> + * Zero on success, or an errno code otherwise.
>> + */
>> +int drm_plane_helper_atomic_check(struct drm_plane *plane,
>> +				  struct drm_atomic_state *new_state)
>> +{
>> +	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(new_state, plane);
>> +	struct drm_crtc *new_crtc = new_plane_state->crtc;
>> +	struct drm_crtc_state *new_crtc_state = NULL;
>> +
>> +	if (new_crtc)
>> +		new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_crtc);
>> +
>> +	return drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
>> +						   DRM_PLANE_NO_SCALING,
>> +						   DRM_PLANE_NO_SCALING,
>> +						   false, false);
>> +}
>> +EXPORT_SYMBOL(drm_plane_helper_atomic_check);
>> diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
>> index 79e8e2017c68..28cf9c87f86d 100644
>> --- a/drivers/gpu/drm/solomon/ssd130x.c
>> +++ b/drivers/gpu/drm/solomon/ssd130x.c
>> @@ -565,22 +565,6 @@ static int ssd130x_fb_blit_rect(struct drm_framebuffer *fb, const struct iosys_m
>>   	return ret;
>>   }
>>   
>> -static int ssd130x_primary_plane_helper_atomic_check(struct drm_plane *plane,
>> -						     struct drm_atomic_state *new_state)
>> -{
>> -	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(new_state, plane);
>> -	struct drm_crtc *new_crtc = new_plane_state->crtc;
>> -	struct drm_crtc_state *new_crtc_state = NULL;
>> -
>> -	if (new_crtc)
>> -		new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_crtc);
>> -
>> -	return drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
>> -						   DRM_PLANE_NO_SCALING,
>> -						   DRM_PLANE_NO_SCALING,
>> -						   false, false);
>> -}
>> -
>>   static void ssd130x_primary_plane_helper_atomic_update(struct drm_plane *plane,
>>   						       struct drm_atomic_state *old_state)
>>   {
>> @@ -623,7 +607,7 @@ static void ssd130x_primary_plane_helper_atomic_disable(struct drm_plane *plane,
>>   
>>   static const struct drm_plane_helper_funcs ssd130x_primary_plane_helper_funcs = {
>>   	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
>> -	.atomic_check = ssd130x_primary_plane_helper_atomic_check,
>> +	.atomic_check = drm_plane_helper_atomic_check,
>>   	.atomic_update = ssd130x_primary_plane_helper_atomic_update,
>>   	.atomic_disable = ssd130x_primary_plane_helper_atomic_disable,
>>   };
>> diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
>> index 777ccd250871..ea5b3239a659 100644
>> --- a/drivers/gpu/drm/tiny/simpledrm.c
>> +++ b/drivers/gpu/drm/tiny/simpledrm.c
>> @@ -469,29 +469,6 @@ static const uint64_t simpledrm_primary_plane_format_modifiers[] = {
>>   	DRM_FORMAT_MOD_INVALID
>>   };
>>   
>> -static int simpledrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
>> -						       struct drm_atomic_state *new_state)
>> -{
>> -	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(new_state, plane);
>> -	struct drm_crtc *new_crtc = new_plane_state->crtc;
>> -	struct drm_crtc_state *new_crtc_state = NULL;
>> -	int ret;
>> -
>> -	if (new_crtc)
>> -		new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_crtc);
>> -
>> -	ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
>> -						  DRM_PLANE_NO_SCALING,
>> -						  DRM_PLANE_NO_SCALING,
>> -						  false, false);
>> -	if (ret)
>> -		return ret;
>> -	else if (!new_plane_state->visible)
>> -		return 0;
>> -
>> -	return 0;
>> -}
>> -
>>   static void simpledrm_primary_plane_helper_atomic_update(struct drm_plane *plane,
>>   							 struct drm_atomic_state *old_state)
>>   {
>> @@ -543,7 +520,7 @@ static void simpledrm_primary_plane_helper_atomic_disable(struct drm_plane *plan
>>   
>>   static const struct drm_plane_helper_funcs simpledrm_primary_plane_helper_funcs = {
>>   	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
>> -	.atomic_check = simpledrm_primary_plane_helper_atomic_check,
>> +	.atomic_check = drm_plane_helper_atomic_check,
>>   	.atomic_update = simpledrm_primary_plane_helper_atomic_update,
>>   	.atomic_disable = simpledrm_primary_plane_helper_atomic_disable,
>>   };
>> diff --git a/include/drm/drm_plane_helper.h b/include/drm/drm_plane_helper.h
>> index 1781fab24dd6..7ba414655d69 100644
>> --- a/include/drm/drm_plane_helper.h
>> +++ b/include/drm/drm_plane_helper.h
>> @@ -41,5 +41,7 @@ int drm_plane_helper_update_primary(struct drm_plane *plane, struct drm_crtc *cr
>>   int drm_plane_helper_disable_primary(struct drm_plane *plane,
>>   				     struct drm_modeset_acquire_ctx *ctx);
>>   void drm_plane_helper_destroy(struct drm_plane *plane);
>> +int drm_plane_helper_atomic_check(struct drm_plane *plane,
>> +				  struct drm_atomic_state *new_state);
>>   
>>   #endif
>> -- 
>> 2.37.1
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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