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

Noralf Trønnes
2020-05-03T10:03:01Z

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@tronnes.org>
> Two small ntis. With these addressed:
> Reviewed-by: Sam Ravnborg <sam@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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