colorkey support for intel i915 gpu driver

[Ville Syrjälä]

On Mon, Apr 01, 2019 at 08:18:13PM +0000, Jim Zhang wrote:
> Hi Sir/Madam:
> 
> I am using the open source Baytrail gpu drm driver.
> 
> Linux kernel version 3.10.61:
> Libdrm package:  2.4.97
> 
> When calling function
> properties = drmModeObjectGetProperties(drmfd, plane_id, DRM_MODE_OBJECT_PLANE);
>  it only returns only one property:
> 
> This property is:
>   property->name = "rotation", property->prop_id =4
> It looks like that the Baytrail gpu drm driver does not support colorkey.

There are two problems currently:
- Destination colorkey is not implemented on BYT/CHV. I have
  patches for it but they have not been reviewed by anyone:
  https://patchwork.freedesktop.org/series/43902/
- Colorkey can only be set via a custom i915 specific ioctl
  (DRM_I915_SET_SPRITE_COLORKEY). There have been a few attempts at
  a generic property based API that never really went anywhere. It's
  a rather difficult problem making this generic as each hardware has
  its own peculiar way of specifying colorkeying. The main problem
  with the custom ioctl is that it's not atomic with other screen
  updates.

So, what kind of use case do you have in mind?

-- 
Ville Syrjälä
Intel