Re: [RFC] PVFB: Add refresh period to XenStore parameters?

[Markus Armbruster <armbru@redhat.com>]

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

> Markus Armbruster, le Tue 04 Mar 2008 18:06:26 +0100, a écrit :
>> Samuel Thibault <samuel.thibault@eu.citrix.com> writes:
>> > Markus Armbruster, le Tue 04 Mar 2008 16:48:20 +0100, a écrit :
>> >> * 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.
>> 
>> Optimize for the common case.  Which I figure is a 32 bpp framebuffer.
>
> Cirrus VGA is 24bpp max :)

I read that as a sign that you're abusing the PVFB stuff for something
it wasn't meant to do: emulating some craptastic piece of vintage junk
:)

>> Anyway, compare and copy for some legacy 80x25 text mode shouldn't eat
>> that much CPU.
>
> Yes.
>
> By my "that's not always the case", I actually expressed the need for
> the offset feature.
>
> Samuel

Let's await the next round of the dynamic mode patch, then see how an
offset could fit in there.