[PATCH 05/10] drm/client: Add drm_client_modeset_check()

[Noralf Trønnes]

Den 03.05.2020 10.03, skrev Sam Ravnborg:
> Hi Noralf.
> 
> On Wed, Apr 29, 2020 at 02:48:25PM +0200, Noralf Trønnes wrote:
>> Add a way for client to check the configuration before comitting.
>>
>> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
> Two small ntis. With these addressed:
> Reviewed-by: Sam Ravnborg <sam at ravnborg.org>
>> ---
>>  drivers/gpu/drm/drm_client_modeset.c | 35 ++++++++++++++++++++++++----
>>  include/drm/drm_client.h             |  1 +
>>  2 files changed, 32 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
>> index 7443114bd713..177158ff2a40 100644
>> --- a/drivers/gpu/drm/drm_client_modeset.c
>> +++ b/drivers/gpu/drm/drm_client_modeset.c
>> @@ -966,7 +966,7 @@ bool drm_client_rotation(struct drm_mode_set *modeset, unsigned int *rotation)
>>  }
>>  EXPORT_SYMBOL(drm_client_rotation);
>>  
>> -static int drm_client_modeset_commit_atomic(struct drm_client_dev *client, bool active)
>> +static int drm_client_modeset_commit_atomic(struct drm_client_dev *client, bool active, bool check)
>>  {
>>  	struct drm_device *dev = client->dev;
>>  	struct drm_plane *plane;
>> @@ -1033,7 +1033,10 @@ static int drm_client_modeset_commit_atomic(struct drm_client_dev *client, bool
>>  		}
>>  	}
>>  
>> -	ret = drm_atomic_commit(state);
>> +	if (check)
>> +		ret = drm_atomic_check_only(state);
>> +	else
>> +		ret = drm_atomic_commit(state);
>>  
>>  out_state:
>>  	if (ret == -EDEADLK)
>> @@ -1094,6 +1097,30 @@ static int drm_client_modeset_commit_legacy(struct drm_client_dev *client)
>>  	return ret;
>>  }
>>  
>> +/**
>> + * drm_client_modeset_check() - Check CRTC configuration
> This part of the comment does not match the description below.
> 
> 
>> + * @client: DRM client
>> + *
>> + * Check modeset configuration.
>> + *
>> + * Returns:
>> + * Zero on success or negative error code on failure.
>> + */
>> +int drm_client_modeset_check(struct drm_client_dev *client)
>> +{
>> +	int ret;
>> +
>> +	if (!drm_drv_uses_atomic_modeset(client->dev))
>> +		return 0;
> If client does not use atomic the check should fail - no?

Returning an error here would result in the client not working with
non-atomic drivers which AFAIK doesn't have a way to check the state
before hand. The client have to commit the state/configuration to find
out if it is good.

Noralf.

> 
>> +
>> +	mutex_lock(&client->modeset_mutex);
>> +	ret = drm_client_modeset_commit_atomic(client, true, true);
>> +	mutex_unlock(&client->modeset_mutex);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(drm_client_modeset_check);
>> +
>>  /**
>>   * drm_client_modeset_commit_locked() - Force commit CRTC configuration
>>   * @client: DRM client
>> @@ -1112,7 +1139,7 @@ int drm_client_modeset_commit_locked(struct drm_client_dev *client)
>>  
>>  	mutex_lock(&client->modeset_mutex);
>>  	if (drm_drv_uses_atomic_modeset(dev))
>> -		ret = drm_client_modeset_commit_atomic(client, true);
>> +		ret = drm_client_modeset_commit_atomic(client, true, false);
>>  	else
>>  		ret = drm_client_modeset_commit_legacy(client);
>>  	mutex_unlock(&client->modeset_mutex);
>> @@ -1188,7 +1215,7 @@ int drm_client_modeset_dpms(struct drm_client_dev *client, int mode)
>>  
>>  	mutex_lock(&client->modeset_mutex);
>>  	if (drm_drv_uses_atomic_modeset(dev))
>> -		ret = drm_client_modeset_commit_atomic(client, mode == DRM_MODE_DPMS_ON);
>> +		ret = drm_client_modeset_commit_atomic(client, mode == DRM_MODE_DPMS_ON, false);
>>  	else
>>  		drm_client_modeset_dpms_legacy(client, mode);
>>  	mutex_unlock(&client->modeset_mutex);
>> diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
>> index 6ef5364d6dfb..b6ffa4863e45 100644
>> --- a/include/drm/drm_client.h
>> +++ b/include/drm/drm_client.h
>> @@ -164,6 +164,7 @@ int drm_client_modeset_create(struct drm_client_dev *client);
>>  void drm_client_modeset_free(struct drm_client_dev *client);
>>  int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width, unsigned int height);
>>  bool drm_client_rotation(struct drm_mode_set *modeset, unsigned int *rotation);
>> +int drm_client_modeset_check(struct drm_client_dev *client);
>>  int drm_client_modeset_commit_locked(struct drm_client_dev *client);
>>  int drm_client_modeset_commit(struct drm_client_dev *client);
>>  int drm_client_modeset_dpms(struct drm_client_dev *client, int mode);
>> -- 
>> 2.23.0
>>
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