On Wed, 03 Nov 2021, Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
> Hi
>
> Am 03.11.21 um 14:41 schrieb Jani Nikula:
>> On Wed, 03 Nov 2021, Javier Martinez Canillas <javierm@xxxxxxxxxx> wrote:
>>> DRM drivers can use this to determine whether they can be enabled or not.
>>>
>>> For now it's just a wrapper around drm_modeset_disabled() but having the
>>> indirection level will allow to add other conditions besides "nomodeset".
>>>
>>> Suggested-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
>>> Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
>>
>> Can't see i915 trivially using this due to the drm_driver
>> parameter. Please let's not merge helpers like this without actual
>> users.
>
> Can you explain?
>
> This would be called on the top of the PCI probe function. The parameter
> would allow to decide on a per-driver base (e.g., to ignore generic
> drivers).
Where and how exactly? This is why we need to see the patch using the
function. A patch is worth a thousand words. ;)
See current vgacon_text_force() usage in i915/i915_module.c. It happens
way before anything related to pci or drm driver. Why bother with the
complicated setup and teardown of stuff if you can bail out earlier?
BR,
Jani.
>
> Best regards
> Thomas
>
>>
>> BR,
>> Jani.
>>
>>
>>> ---
>>>
>>> drivers/gpu/drm/drm_drv.c | 21 +++++++++++++++++++++
>>> include/drm/drm_drv.h | 1 +
>>> 2 files changed, 22 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>>> index 8214a0b1ab7f..70ef08941e06 100644
>>> --- a/drivers/gpu/drm/drm_drv.c
>>> +++ b/drivers/gpu/drm/drm_drv.c
>>> @@ -975,6 +975,27 @@ int drm_dev_set_unique(struct drm_device *dev, const char *name)
>>> }
>>> EXPORT_SYMBOL(drm_dev_set_unique);
>>>
>>> +/**
>>> + * drm_drv_enabled - Checks if a DRM driver can be enabled
>>> + * @driver: DRM driver to check
>>> + *
>>> + * Checks whether a DRM driver can be enabled or not. This may be the case
>>> + * if the "nomodeset" kernel command line parameter is used.
>>> + *
>>> + * Returns:
>>> + * True if the DRM driver is enabled and false otherwise.
>>> + */
>>> +bool drm_drv_enabled(const struct drm_driver *driver)
>>> +{
>>> + if (drm_modeset_disabled()) {
>>> + DRM_INFO("%s driver is disabled\n", driver->name);
>>> + return false;
>>> + }
>>> +
>>> + return true;
>>> +}
>>> +EXPORT_SYMBOL(drm_drv_enabled);
>>> +
>>> /*
>>> * DRM Core
>>> * The DRM core module initializes all global DRM objects and makes them
>>> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
>>> index 0cd95953cdf5..48f2b6eec012 100644
>>> --- a/include/drm/drm_drv.h
>>> +++ b/include/drm/drm_drv.h
>>> @@ -598,5 +598,6 @@ static inline bool drm_drv_uses_atomic_modeset(struct drm_device *dev)
>>>
>>> int drm_dev_set_unique(struct drm_device *dev, const char *name);
>>>
>>> +bool drm_drv_enabled(const struct drm_driver *driver);
>>>
>>> #endif
>>
--
Jani Nikula, Intel Open Source Graphics Center
