Re: Losing interrupts

[Andrew Morton <akpm@osdl.org>]

Lee Revell <rlrevell@joe-job.com> wrote:
>
> There was an issue several years ago where Matrox figured out they could
> get slightly better benchmark scores by not checking whether a FIFO on
> the video card was full before writing to it, which would cause the PCI
> bus to completely freeze until the FIFO had drained.  Lots of vendors
> followed suit until one of the audio software vendors figred it out and
> called them on it, at which point they fixed their drivers.  The effects
> (massive audio drouputs) and the steps to reproduce (drag a window
> around the screen slowly) were identical.

There's an XF86Config incantation which is supposed to prevent this: if you
set it, the driver will poll the FIFO-full bit before actually reading the
FIFO.

hm, according to http://www.xfree86.org/3.3.6/3DLabs3.html, the pci_retry
option _causes_ the bad behaviour, rather than avoiding it.

Oh, well.  Have a play with that.