[mythtv-users] does setpci latency_timer fail on some mobos?

Jonathan Rogers jonner at teegra.net
Tue Jun 5 13:33:06 UTC 2007


On Sat, 2007-06-02 at 07:38 -0400, Brian L. Walter wrote:
> Brian Wood wrote:
> > Mark A. Miller wrote:
> >   
> >> I have been experimenting with MythTV recently.  After experimenting
> >> with assorted hardware and distros, my video is fairly good, but I get
> >> an occasional hiccup, especially in action scenes.  When I try to set
> >> the latency on the SATA controller to something high like AA, it stays
> >> at 0 (see configuration and screendump below.)
> >>
> >> My questions:
> >> # Is the concept of PCI latency relevant on a PCIe system?  Are my
> >> integrated controllers like the SATA on PCI or PCIe?

I don't know if the PCI latency timer is still relevant for PCIe. As one
data point, I have a Via-based board with onboard PCIe network adapter
and onboard PCI SATA and IDE (PATA) interfaces. lspci reports reasonable
values for latency on the SATA and IDE devices, but the PCIe video card
and onboard PCIe network adapter have 0. I haven't tried adjusting any
values on that system, since I don't seem to have IO problems. I suspect
newer motherboards might have PCIe SATA adapters, since PCI can't
support the maximum throughput of SATA.

You're using a PVR-x50, right? It seems unlikely that you'd be running
into IO starvation problems. I'm using my system for HD and I don't seem
to be running into that.
-- 
Jonathan Rogers <jonner at teegra.net>
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