PVFB: Add offset event? (Was PVFB: Add refresh period to XenStore parameters?)

PVFB: Add offset event? (Was PVFB: Add refresh period to XenStore parameters?)

[Samuel Thibault]

Samuel Thibault, le Tue 04 Mar 2008 16:12:20 +0000, a écrit :
> Markus Armbruster, le Tue 04 Mar 2008 16:48:20 +0100, a écrit :
> > I imagine (perhaps naively):
> > 
> > * The domU writes to a framebuffer provided by the frontend.
> >
> > * The framebuffer (not a copy of it) can be shared with the backend,
> >   which only reads.
> 
> Well, that's not always the case, when the guest is in text mode for
> instance, the PV shared buffer is converted from the guest text buffer.

BTW, that leads me to another extension which would be useful: since
the interface I have with the guest is the cirrus VGA card, I'm not
supposed to know in advance where the guest will choose to make its
frame buffer start, so at the same time of a resize event, or as an
independant event, it would be useful to be able to tell the offset
(within the big shared buffer) where the actual framebuffer starts.

Samuel

Re: PVFB: Add offset event?

[Markus Armbruster]

Samuel Thibault <samuel.thibault@eu.citrix.com> writes:

> Samuel Thibault, le Tue 04 Mar 2008 16:12:20 +0000, a écrit :
>> Markus Armbruster, le Tue 04 Mar 2008 16:48:20 +0100, a écrit :
>> > I imagine (perhaps naively):
>> > 
>> > * The domU writes to a framebuffer provided by the frontend.
>> >
>> > * The framebuffer (not a copy of it) can be shared with the backend,
>> >   which only reads.
>> 
>> Well, that's not always the case, when the guest is in text mode for
>> instance, the PV shared buffer is converted from the guest text buffer.
>
> BTW, that leads me to another extension which would be useful: since
> the interface I have with the guest is the cirrus VGA card, I'm not
> supposed to know in advance where the guest will choose to make its
> frame buffer start, so at the same time of a resize event, or as an
> independant event, it would be useful to be able to tell the offset
> (within the big shared buffer) where the actual framebuffer starts.
>
> Samuel

I guess that could be worked into the dynamic modes feature.