KMS cursor BO semantics

[Ilija Hadzic]

On Fri, 4 Nov 2011, Thomas Hellstrom wrote:

> Hi.
>
> I have a question about the semantics of the DRM_IOCTL_MODE_CURSOR iotcl:
>
> Some hardware (vmware's virtual in particular) may not be able to pick up the 
> changes from a bo directly, since the cursor data is sent though the command 
> stream. Hence we need a notification when the cursor image has changed.
>
> Could we *require* that a cursor image change needs to be followed by an 
> ioctl call with the flag
> DRM_MODE_CURSOR_BO?
>
> Thanks,
> Thomas
>

FWIW, Acked-by: Ilija Hadzic <ihadzic at research.bell-labs.com>
I have a few places where I could use such an ioctl.

BTW, Thomas, in the above "since the cursor data is sent though the 
command stream", did you mean "since the cursor data is *not* sent though 
the command stream". If it was sent, through command stream, then CS ioctl 
would know when the cursor changes.

My understanding is that the cursor data are mmap-ed letting userland poke 
it at will (so the case when an "hourglass" changes into "arrow" is 
particularly hard to know that it happened).

-- Ilija