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Re: mm->mmap_sem
On Thu, 30 Sep 1999, Stephen C. Tweedie wrote:
> Hi,
>
> On Mon, 27 Sep 1999 15:31:28 -0400 (EDT), James Simmons
> <jsimmons@edgeglobal.com> said:
>
> > What are all the broken cards out their? I was reading my old Matrox
> > Millenium I docs and even that card supports similutaneous access to
> > the accel engine and framebuffer. If the number of cards that are that
> > broken are small then I just will not support them.
>
> I think that there's a large number of them. The XI and XFree86 folk
> would probably know which ones exactly.
Yikes. I think the best solution is to just put the process that owns
the framebuffer to be put to sleep just before accel engine access. Wake
it up once its done. Some fancy scheduling tricks should do it. I have it
setup now that accels used internal in the kernel to speed up console
rendering will not work when /dev/fb is mmapped. Also I have set it up so
only one process can open /dev/fb at a time. This makes life much easier.
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