Playing DVD interfers with modem?
Rick Stevens
rstevens at internap.com
Mon Feb 4 19:55:36 UTC 2008
On Fri, 2008-02-01 at 16:34 -0500, Ric Moore wrote:
> On Fri, 2008-02-01 at 09:59 -0800, Rick Stevens wrote:
> > On Fri, 2008-02-01 at 00:19 -0500, Ric Moore wrote:
> > > When I play a video DVD the modem quits doing whatever it's doing.
> > > Strange. I'm running 32bit FC7 on a system with a 64bit AMD 3200 and 2
> > > gigs of memory. Both Xine and VLC exhibit the same behavior. I just
> > > tried gmplayer and it does the same thing, but the sound has static.
> > > That's weird, it never has before. Something else to fix. Sound on Xine
> > > or VLC is perfect.
> >
> > Uh, are the modem and the IDE port the DVD sharing an IRQ or something?
> >
> > > So, how could playing a DVD foul up the modem? Is there some type of
> > > streaming to the network that could grab the serial line or the ppp
> > > session??
> >
> > I can think of two things at least...the sharing of an IRQ or some other
> > hardware semaphore or simply the load put on the CPU by a soft modem.
> > However, with an AMD 3200, I don't think that's the issue.
>
> Lordy Rick, I'm an old BBS sysop from back when. I have a RS Robotics
> external with all the bells and whistles in hardware, so I'm connected
> only by a serial cable. I'm gonna check out your suggestion about the
> IRQ though. I sure miss setting pin jumpers. Devices generally stayed
> where you put 'em, IRQ wise. Here's /proc/interrupts
>
> # more interrupts
> CPU0
> 0: 181 IO-APIC-edge timer
> 1: 21093 IO-APIC-edge i8042
> 7: 0 IO-APIC-edge parport0
> 8: 1 IO-APIC-edge rtc
> 9: 1 IO-APIC-fasteoi acpi
> 12: 4 IO-APIC-edge i8042
> 14: 45395 IO-APIC-edge libata
> 15: 0 IO-APIC-edge libata
> 16: 986 IO-APIC-fasteoi ohci_hcd:usb1
> 17: 122468 IO-APIC-fasteoi ohci_hcd:usb2
> 18: 0 IO-APIC-fasteoi ohci_hcd:usb3
> 19: 3 IO-APIC-fasteoi ehci_hcd:usb4
> 20: 71311 IO-APIC-fasteoi libata
> 21: 566805 IO-APIC-fasteoi ALi M5455, eth0
> 22: 1327729 IO-APIC-fasteoi nvidia
> NMI: 0
> LOC: 2874529
> ERR: 0
> MIS: 0
>
> I don't see IRQ 3 or 4 listed for serial port. Do I have to gink with
> uugetty or set serial? Is that the right place to look?? Ric
The IRQ won't show up unless something is on the serial port or using
it. For example, my machine shows this normally:
0: 1668 IO-APIC-edge timer
1: 163398 IO-APIC-edge i8042
6: 6 IO-APIC-edge floppy
However, if I "agetty -L 9600 ttyS0", it shows this:
0: 1668 IO-APIC-edge timer
1: 163146 IO-APIC-edge i8042
4: 25 IO-APIC-edge serial
6: 6 IO-APIC-edge floppy
So, you need to look at it when the modem's active (or you've spawned
something like agetty on it).
----------------------------------------------------------------------
- Rick Stevens, Principal Engineer rstevens at internap.com -
- CDN Systems, Internap, Inc. http://www.internap.com -
- -
- Never put off 'til tommorrow what you can forget altogether! -
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