Synchronization with CRT refresh
Michel Dänzer
michel at daenzer.net
Tue May 3 11:32:04 PDT 2005
On Tue, 2005-05-03 at 12:35 -0400, Jim Gettys wrote:
> On Tue, 2005-05-03 at 11:58 -0400, Adam Jackson wrote:
> > On Tuesday 03 May 2005 11:02, Jim Gettys wrote:
> > > Unfortunately, this has never been implemented on Linux.
> > >
> > > Volunteers gratefully accepted...
> >
> > I looked at doing this for i128 a while ago, and there's a few issues involved
> > in getting it right. The simple first one is actually wiring up the sync
> > counter from the driver, afaict there's no existing driver infrastructure for
> > this. Is there any sample implementation of a driver that exports a sync
> > counter?
>
> Not commonly available: we did implementations on closed source UNIX in
> the early 1990's. Alan Cox started on a kernel framework for this for
> Linux to plug into just before he went to graduate school; I don't know
> what happened to the code.
Ahem. I implemented this in the DRM years ago. I even extended the
interface to optionally generate a signal instead of blocking in the
ioctl on request by yours truly and Keith Packard, but I'm still not
aware of anything using that. Oh well.
--
Earthling Michel Dänzer | Debian (powerpc), X and DRI developer
Libre software enthusiast | http://svcs.affero.net/rm.php?r=daenzer
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