Intel Q35/Q45 fb driver?

McDonald, Michael-p7438c Michael.McDonald at
Thu Oct 8 18:43:16 PDT 2009

> -----Original Message-----
> From: Pat Kane [mailto:pekane52 at] 
> Sent: Wednesday, October 07, 2009 7:38 PM
> To: McDonald, Michael-p7438c
> Cc: Adam Jackson; xorg at
> Subject: Re: Intel Q35/Q45 fb driver?
>  On Wed, Oct 7, 2009 at 8:40 PM, McDonald, Michael-p7438c
> <Michael.McDonald at> wrote:
>  > We have the mmap version of the MIT SHM extension working 
> and we now get
>  > 18-21 frames/sec whereas we were getting just 2-3 
> frames/sec using stock
>  > X.
> Nice, I'd like to take a look at your changes.

Our current implementation is pretty kludgy. We overloaded the
XShmSegmentInfo struct by using shmid's less than -1 to mean use mmap()
and added fields for the filename and size. Then in the server, we
modified ProcShmAttach and ShmDetachSegment to recognize the shmid less
than -1 and use mmap/munmap instead of shmat/shmdt.

To do this "right", we should introduce our own request/response structs
and their own Proc routines. Maybe with a user interface with something

	XShmMmap(Display *, XShmSegmentInfo *, char *filename, CARD32

So anyway, we need to do some clean up and then see if our management is
willing to let us contribute the changes back, assuming anyone is still
interested at that point.

Mike McDonald

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