[mythtv-users] Experiencing lockups since upgrade to 2.6.17

[chris at cpr.homelinux.net]

On Fri, Sep 08, 2006 at 12:59:33PM -0700, Mik Rose wrote:
> I am having the same issue with intermittent lock ups, during the viewing of
> live tv.
>      On 7/3/06, John Freer <john_freer at yahoo.com> wrote:
>           Could use some suggestions.  I'm experiencing frequent hard
>           lockups (every few hours or so) now since I've migrated my
>           FC4 system over to 2.6.17 as of this weekend.
> 
>           Seems to correlate to when commercial flagging is going
>           on.  I don't have to be doing anything (mythfrontend is at
>           main menu) for the lockup to occur.

Assuming you are using the ivtv driver, most of the lockup and 
video artifacting problems seem to be caused by PCI DMA problems, 
and would happen any time the PCI or IDE channels were saturated 
regardless of what you were doing at the time.  Watching live TV 
while commercial flagging seems to be an almost worst-case 
scenario, but I've managed to get my mythbackend to lockup while 
doing other disk-intensive tasks that didn't involve MythTV at all.

Some mobos are more affected than others because of flaws in their 
APIC/ACPI design.  Turning off APIC support seems to reduce the DMA 
errors, but at the expense of much higher CPU usage.  There also 
seems to be some issues with CPU frequency throttling causing the 
DMA interrupts to get lost.

The ivtv people are working on it.  From what I've seen on the ivtv 
mailing list a solution for the PVR-150/250/500 may be forthcoming 
but the PVR-350 seems to be a lost cause.