[PATCH v3 04/81] drm: Add client-agnostic setup helper

[Geert Uytterhoeven]

 	Hi Thomas,

On Fri, 30 Aug 2024, Thomas Zimmermann wrote:
> DRM may support multiple in-kernel clients that run as soon as a DRM
> driver has been registered. To select the client(s) in a single place,
> introduce drm_client_setup().
>
> Drivers that call the new helper automatically instantiate the kernel's
> configured default clients. Only fbdev emulation is currently supported.
> Later versions can add support for DRM-based logging, a boot logo or even
> a console.
>
> Some drivers handle the color mode for clients internally. Provide the
> helper drm_client_setup_with_color_mode() for them.
>
> v3:
> - fix build error
> v2:
> - add drm_client_setup_with_fourcc() (Laurent)
> - push default-format handling into actual clients
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>

Thanks for your patch!

> --- /dev/null
> +++ b/drivers/gpu/drm/drm_client_setup.c

> +/**
> + * drm_client_setup_with_fourcc() - Setup in-kernel DRM clients for color mode
> + * @dev: DRM device
> + * @fourcc: Preferred pixel format as 4CC code for the device
> + *
> + * This function sets up the in-kernel DRM clients. It is equivalent
> + * to drm_client_setup(), but expects a 4CC code as second argument.
> + *
> + * Do not use this function in new drivers. Prefer drm_client_setup() with a
> + * format of NULL.

Why? To me this looks like the right function to call on hardware
that does not support ARGB8888 natively.

BTW, once this series is applied, I plan to check again how to wire up
native fbcon support for monochrome (DRM_FORMAT_R1) and grayscale
(DRM_FORMAT_R8), as used by the Solomon driver.

> + */
> +void drm_client_setup_with_fourcc(struct drm_device *dev, u32 fourcc)
> +{
> +	drm_client_setup(dev, drm_format_info(fourcc));
> +}
> +EXPORT_SYMBOL(drm_client_setup_with_fourcc);
> +
> +/**
> + * drm_client_setup_with_color_mode() - Setup in-kernel DRM clients for color mode
> + * @dev: DRM device
> + * @color_mode: Preferred color mode for the device
> + *
> + * This function sets up the in-kernel DRM clients. It is equivalent
> + * to drm_client_setup(), but expects a color mode as second argument.
> + *
> + * Do not use this function in new drivers. Prefer drm_client_setup() with a


Yeah, this is definitely not to be used in new drivers, as color_mode is
ambiguous.

> + * format of NULL.

or drm_client_setup_with_fourcc().

> + */
> +void drm_client_setup_with_color_mode(struct drm_device *dev, unsigned int color_mode)
> +{
> +	u32 fourcc = drm_driver_color_mode_format(dev, color_mode);
> +
> +	drm_client_setup_with_fourcc(dev, fourcc);
> +}
> +EXPORT_SYMBOL(drm_client_setup_with_color_mode);

Gr{oetje,eeting}s,

 						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
 							    -- Linus Torvalds