Re: [PATCH v3 2/3] drm/fb-cma-helper: expose more of fb cma guts

Boris Brezillon
2017-06-19T20:41:21Z

Le Mon, 19 Jun 2017 09:44:25 +0200,
Peter Rosin <peda@axentia.se> a écrit :

> DRM drivers supporting clut may want a convenient way to only use
> non-default .gamma_set and .gamma_get ops in the drm_fb_helper_funcs
> in order to avoid the following
>
> /*
> * The driver really shouldn't advertise pseudo/directcolor
> * visuals if it can't deal with the palette.
> */
> if (WARN_ON(!fb_helper->funcs->gamma_set ||
> !fb_helper->funcs->gamma_get))
> return -EINVAL;
>
> warning in drm_fb_helper.c:setcolreg().

Did you read the FIXME in the struct doc [1]? Shouldn't we try to move
to this generic approach instead of exposing fb_cma internals? You
could probably mimic (or re-use) what's done in
drm_mode_gamma_set/get_ioctl() [2].

[1]http://elixir.free-electrons.com/linux/v4.12-rc6/source/include/drm/drm_fb_helper.h#L110
[2]http://elixir.free-electrons.com/linux/v4.12-rc6/source/drivers/gpu/drm/drm_color_mgmt.c#L214