[PATCH v2 7/8] drm/display: Move HDMI helpers into display-helper module

[Javier Martinez Canillas]

On 4/20/22 14:21, Thomas Zimmermann wrote:
> Hi
> 
> Am 20.04.22 um 14:02 schrieb Javier Martinez Canillas:
>> Hello Thomas,
>>
>> On 4/20/22 13:08, Thomas Zimmermann wrote:
>>
>> [snip]
>>
>>> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> @@ -1,6 +1,8 @@
>>>   # SPDX-License-Identifier: GPL-2.0-only
>>>   config DRM_DW_HDMI
>>>   	tristate
>>> +	select DRM_DISPLAY_HDMI_HELPER
>>> +	select DRM_DISPLAY_HELPER
>>>   	select DRM_KMS_HELPER
>>>   	select REGMAP_MMIO
>>>   	select CEC_CORE if CEC_NOTIFIER
>>
>> [snip]
>>
>>> +config DRM_DISPLAY_HDMI_HELPER
>>> +	bool
>>> +	select DRM_DISPLAY_HELPER
>>> +	help
>>> +	  DRM display helpers for HDMI.
>>> +
>>
>> Maybe you mentioned already when we discussed it in v1, but could
>> you please remember me why we need to select both symbols for the
>> drivers, even when DRM_DISPLAY_HELPER is already selected here ?
>>
>> Or are select operations not transitive ?
> 
> DRM_DISPLAY_HELPER enables the module itself. It's tristate. 
> DRM_DISPLAY_HDMI_HELPER, DRM_DISPLAY_DP_HELPER, etc are the individual 
> features of the helper module. Each is a boolean.  Drivers can enable 
> them according to their needs.  This split allows linking correctly in 
> all cases, even if some drivers are built-in and others are modules. 
> This didn't always work with the original patches.
>
Right, but that wasn't my question. I wondered why for example DRM_DW_HDMI
Kconfig needs to select both DRM_DISPLAY_HDMI_HELPER and DRM_DISPLAY_HELPER
since DRM_DISPLAY_HDMI_HELPER already selects DRM_DISPLAY_HELPER.

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat