[Intel-gfx] [PATCH v2 1/6] drm: Include the encoder itself in possible_clones

[Thomas Zimmermann]

Hi

Am 07.02.20 um 17:27 schrieb Daniel Vetter:
> On Fri, Feb 07, 2020 at 04:50:01PM +0200, Ville Syrjälä wrote:
>> On Fri, Feb 07, 2020 at 03:28:35PM +0100, Thomas Zimmermann wrote:
>>> Hi
>>>
>>> Am 07.02.20 um 14:59 schrieb Ville Syrjala:
>>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>>
>>>> The docs say possible_clones should always include the encoder itself.
>>>> Since most drivers don't want to deal with the complexities of cloning
>>>> let's allow them to set possible_clones=0 and instead we'll fix that
>>>> up in the core.
>>>>
>>>> We can't put this special case into drm_encoder_init() because drivers
>>>> will have to fill up possible_clones after adding all the relevant
>>>> encoders. Otherwise they wouldn't know the proper encoder indexes to
>>>> use. So we'll just do it just before registering the encoders.
>>>>
>>>> TODO: Should we do something similar for possible_crtcs==0?
>>>>
>>>> Cc: Thomas Zimmermann <tzimmermann at suse.de>
>>>> Cc: Daniel Vetter <daniel at ffwll.ch>
>>>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>
>>> May this fixup function should warn iff possible_clones was set to non-0
>>> by the driver, but the encoder itself is missing.
>>
>> Yeah, I guess we could do that.
> 
> +1 on that, should catch some bugs at least.
> 
> Also can you pls fix up the kerneldoc for drm_encoder.possible_clones,
> defacto this now means that 0 is a totally fine setting.

Just a thought: we should encourage, or maybe even require, the use of
such defaults (i.e., 0); unless a driver has a good reason to override
them. So we don't have to fix drivers if the defaults ever change.

Best regards
Thomas

> -Daniel
> 
>>
>>> In any case
>>>
>>> Acked-by: Thomas Zimmermann <tzimmermann at suse.de>
>>>
>>>> ---
>>>>  drivers/gpu/drm/drm_encoder.c | 15 +++++++++++++++
>>>>  1 file changed, 15 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
>>>> index e555281f43d4..f761d9306028 100644
>>>> --- a/drivers/gpu/drm/drm_encoder.c
>>>> +++ b/drivers/gpu/drm/drm_encoder.c
>>>> @@ -66,11 +66,26 @@ static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
>>>>  	{ DRM_MODE_ENCODER_DPI, "DPI" },
>>>>  };
>>>>  
>>>> +/*
>>>> + * For some reason we want the encoder itself included in
>>>> + * possible_clones. Make life easy for drivers by allowing them
>>>> + * to leave possible_clones unset if no cloning is possible.
>>>> + */
>>>> +static void fixup_possible_clones(struct drm_device *dev)
>>>> +{
>>>> +	struct drm_encoder *encoder;
>>>> +
>>>> +	drm_for_each_encoder(encoder, dev)
>>>> +		encoder->possible_clones |= drm_encoder_mask(encoder);
>>>> +}
>>>> +
>>>>  int drm_encoder_register_all(struct drm_device *dev)
>>>>  {
>>>>  	struct drm_encoder *encoder;
>>>>  	int ret = 0;
>>>>  
>>>> +	fixup_possible_clones(dev);
>>>> +
>>>>  	drm_for_each_encoder(encoder, dev) {
>>>>  		if (encoder->funcs->late_register)
>>>>  			ret = encoder->funcs->late_register(encoder);
>>>>
>>>
>>> -- 
>>> Thomas Zimmermann
>>> Graphics Driver Developer
>>> SUSE Software Solutions Germany GmbH
>>> Maxfeldstr. 5, 90409 Nürnberg, Germany
>>> (HRB 36809, AG Nürnberg)
>>> Geschäftsführer: Felix Imendörffer
>>>
>>
>>
>>
>>
>> -- 
>> Ville Syrjälä
>> Intel
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 

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

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