KMS cursor BO semantics

[Maarten Maathuis]

On Fri, Nov 11, 2011 at 8:10 PM, Maarten Maathuis <madman2003 at gmail.com> wrote:
> On Fri, Nov 11, 2011 at 7:17 PM, James Simmons <jsimmons at infradead.org> wrote:
>>
>>> On Fri, Nov 04, 2011 at 11:30:06PM +0100, Thomas Hellstrom wrote:
>>> > I'm not sure whether / how you handle the case of hardware render to
>>> > cursor surfaces on i915, but it seems to me like if a lot of drivers
>>> > need to implement driver specific "tricks" to meet the semantics of
>>> > a generic interface, we should perhaps consider specifying those
>>> > semantics in a way that helps avoid driver-specific workarounds?
>>>
>>> We don't handle really hanlde rendering to cursor objects. I think the
>>> "require a set_cursor after every cursor bo change" semantic is good, I've
>>> just feared that when only vmgfx needs this, no generic kms user will
>>> actually implement it. But nouveau seems to require this too, so I think
>>> at least for this case reality (and generic kms clients) will play along.
>>
>> I know this is a bit off topic but I see two approaches to the cursor api.
>> One is the nouveau method which is
>>
>> ...
>>        drm_gem_object_lookup
>>        internal_mmap gem object
>>        copy to another internally allocated buffer objec
>>        unmap gem object
>>        drm_gem_object_unreference_unlocked
>> ...
>>
>> Or the radeon approach
>>
>> ...
>>        drm_gem_object_lookup
>>        gem_object_pin
>>        program cursor location
>>        gem_object_unpin
>>        drm_gem_object_unreference_unlocked
>> ...
>>
>> What are the pros and cons to each method?
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>> dri-devel at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>>
>
> Copying means you can convert the cursor to another format if needed.
>
> --
> Far away from the primal instinct, the song seems to fade away, the
> river get wider between your thoughts and the things we do and say.
>

Also no worries about strange side effects if people decide to render
to the cursor. Although i don't know if this is really an issue.

-- 
Far away from the primal instinct, the song seems to fade away, the
river get wider between your thoughts and the things we do and say.