[PATCH v5 2/7] drm/atomic-helper: Add format-conversion state to shadow-plane state

[Javier Martinez Canillas]

Maxime Ripard <mripard at kernel.org> writes:

> On Mon, Oct 09, 2023 at 04:22:29PM +0200, Javier Martinez Canillas wrote:
>> Thomas Zimmermann <tzimmermann at suse.de> writes:
>> > Store an instance of struct drm_format_conv_state in the shadow-plane
>> > state struct drm_shadow_plane_state. Many drivers with shadow planes
>> > use DRM's format helpers to copy or convert the framebuffer data to
>> > backing storage in the scanout buffer. The shadow plane provides the
>> > necessary state and manages the conversion's intermediate buffer memory.
>> >
>> 
>> I would argue this is one of the primary selling points for this series
>> (since Maxime was asking about the motivation). As you point out, many
>> drivers that use a shadow-buffer can also expose a different format than
>> the native one to user-space, so makes sense to have the buffer used for
>> conversion as a part of the shadow-plane state.
>
> I'm confused, can we convert between formats or not? Or is it about
> XRGB8888 vs whatever native format is used by the device?
>

It is about the latter, converting XRGB8888 to the native format.

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat