Re: [Intel-gfx] [PATCH v3 1/1] drm/i915: Enabling 128x128 and 256x256 ARGB Cursor Support

[Daniel Vetter]

On Mon, Mar 10, 2014 at 11:04 AM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
>> > The cap exposes the max cursor size. Knowing our hardware we can infer
>> > that pot sizes from 64 to max are supported, but it would be better if
>> > we did expose that information through the cap as well.
>>
>> I think the right approach here is to expose this through the
>> cursor-as-real-plane interface, which kinda has this already. On top
>> of that we can then add a few fourcc enumerations of the fixed rgba
>> cursor layouts like 64x64, 128x128, ... This helps if the plane is a
>> general one with very high limits, but also with special support for
>> cursor formats.
>>
>> If anyone wants to go crazy we could then also add new fourccs for all
>> the other cursor layouts - atm only rgba with fixed dimensions can be
>> support with the current cursor ioctl.
>>
>> So reviewing the overall situation I actually _don't_ want a new
>> cap/ioctl/prop here just for now. As long as we need to go with intel
>> specific hacks userspace might as well probe things manually and act
>> upon the -EINVAL.
>
> Adding the cap allows existing userspace to dtrt...

1. Move cursor off-screen.
2. Check desired cursor layout with set_cursor.
3. Pick real cursor, set it.

Or

1. Use set_cursor on disabled crtc.

Both aren't pretty, but that ugly should help to move
cursors-as-real-planes forward ;-)
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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