[PATCH] [rfc] drm: add some caps for userspace to discover more info for dumb KMS driver

[Dave Airlie]

On Thu, Sep 29, 2011 at 7:41 PM, Alan Cox <alan at lxorguk.ukuu.org.uk> wrote:
> On Thu, 29 Sep 2011 16:26:32 +0100
> Dave Airlie <airlied at gmail.com> wrote:
>
>> From: Dave Airlie <airlied at redhat.com>
>>
>> For the simple KMS driver case we need some more info about argb cursor
>> limits and a preferred depth and if shadowed framebuffer access is preferred.
>>
>> I've only added this for intel/radeon which support the dumb ioctls so far.
>>
>> I really don't want to expose a truck load of info, just enough for X to
>> start without configuration with a hw cursor.
>
> Actually there is probably one other thing to report - which is whether
> the buffers are cached. That general piece of info "front/back buffer
> cached/uncached" allows you to both make intelligent decisions about
> using back buffers and also about which copy algorithms to use.

I don't think that matters for this driver, its totally not for
acceleration, write a real driver if you have some case where copying
algorithms are going to matter.

The shadow flag is just to let X know back/front is preferred by
default, I don't see a need for anymore info beyond that.

> Also you call this max cursor width - in some devices isn't it actually a
> fixed cursor width ?

Yeah thats a good question, its probably is more of a fixed size
pixmap w/h alright.

Dave.