[mythtv-users] OT? /proc/pci

[Joseph A. Caputo]

On Thursday 15 July 2004 10:05, Sean Covel wrote:
> Sean Covel wrote:
> > Tim Tait wrote:
> >> Jason Kraftcheck wrote:
> >>> Joel Anderson wrote:
> >>>> Marc-David Meijer wrote:
> >>>>
> >>>> As I understand it, PCI devices don't depend on IRQs anyway. 
> >>>> They use interrupt "channels", and IRQs are just kept around to
> >>>> keep legacy stuff
> >>>> happy.  You will often see many devices appear to "share" the
> >>>> same IRQ, but it is not really true since IRQ's can't really
> >>>> _be_ shared.
> >>>>
> >>>> Someone please comment if I haven't explained this correctly. 
> >>>> It's a simplification, but it basically means that IRQ issues
> >>>> shouldn't come into play unless you have some legacy hardware in
> >>>> the system also.
> >>>
> >>> I'm no expert either, but I think they are actually "shared". 
> >>> The interrupt handler must poll each device by invoking the
> >>> interrupt handler in the driver for each device sharing the
> >>> interrupt.  Thus there's a slight performance loss when sharing
> >>> interrupts, and also the possibility for buggy drivers to
> >>> interfere with each other.
> >>
> >> Newer PCI devices support "Message Signalled Interrupts" which use
> >> no physical IRQ line, but instead write a pre-configured value to
> >> the PCI bridge inbound MSI register to cause a unique interrupt. I
> >> can't say for sure the 250MCE actually does that (or that the
> >> driver sets it up that way) but it is possible.  People have
> >> commented eslwhere on the list that it appears the 250MCE needs a
> >> PCI Rev 2.2 compliant motherboard, so you might want to check your
> >>  mobo docs out and see if it complies.
> >
> > Tim,
> >
> > That's probably it.  The mobo of my backend box is OLD.  Its
> > running 2 PIII 600Mhz Slot 1 procs and the on-board IDE is only
> > UDMA33.  OLD!  My "play" machine is running 2 PIII 1.2Mhz Server
> > procs.  Guess its time to swap the MythTv backend to the "play"
> > machine.
> >
> > The "play" machine does recognize the card, now I need to spend the
> > time to get IVTV working on it.  I'm sure it will work now that
> > lspci recognizes the card.
> >
> > Thanks for all your help guys!!!
> >
> > Sean
>
> HELP!!!
>
> What is this card anyway?
>
> 0000:00:0c.0 Multimedia video controller: Conexant Winfast TV2000 XP
> (rev 05)
>          Subsystem: Hauppauge computer works Inc.: Unknown device
> 2801 Flags: bus master, medium devsel, latency 32, IRQ 16 Memory at
> dd000000 (32-bit, non-prefetchable)
>          Capabilities: [44] Vital Product Data
>          Capabilities: [4c] Power Management version 2
>
> 0000:00:0c.1 Multimedia controller: Conexant: Unknown device 8801
> (rev 05) Subsystem: Hauppauge computer works Inc.: Unknown device
> 2801 Flags: bus master, medium devsel, latency 32, IRQ 16 Memory at
> de000000 (32-bit, non-prefetchable)
>          Capabilities: [4c] Power Management version 2
>
> 0000:00:0c.2 Multimedia controller: Conexant: Unknown device 8802
> (rev 05) Subsystem: Hauppauge computer works Inc.: Unknown device
> 2801 Flags: bus master, medium devsel, latency 32, IRQ 16 Memory at
> df000000 (32-bit, non-prefetchable)
>          Capabilities: [4c] Power Management version 2
>
> IVTV loads, but I never get the correct video device /dev/video0.  I
> was under the assumption that ivtv created the devices?


Ummm... are you sure you have a PVR-250MCE?  'Cuz that looks like a 
Winfast TV2000 XP, which IIRC is not supported by the IVTV driver.  Or 
am I being an idiot?

-JAC