IRQ assignment on my IBM X24

ron minnich rminnich at lanl.gov
Mon Apr 7 09:52:00 CEST 2003


On 6 Apr 2003, Eric W. Biederman wrote:

> ron minnich <rminnich at lanl.gov> writes:
> 
> > this seems really poor bios design:
> > @mini rminnich]#  lspci -v -v | grep Interrupt
> >         Interrupt: pin A routed to IRQ 11
> >         Interrupt: pin B routed to IRQ 11
> >         Interrupt: pin C routed to IRQ 11
> >         Interrupt: pin A routed to IRQ 11
> >         Interrupt: pin B routed to IRQ 11
> >         Interrupt: pin B routed to IRQ 11
> >         Interrupt: pin B routed to IRQ 11
> >         Interrupt: pin A routed to IRQ 11
> >         Interrupt: pin A routed to IRQ 11
> >         Interrupt: pin B routed to IRQ 11
> >         Interrupt: pin A routed to IRQ 11
> >         Interrupt: pin A routed to IRQ 11
> > 
> > Pretty much everyone goes to IRQ 11.
> > 
> > And a bunch of Interrupts go unused:
> > 
> >            CPU0       
> >   0:    3381694          XT-PIC  timer
> >   1:      13873          XT-PIC  keyboard
> >   2:          0          XT-PIC  cascade
> >   8:          1          XT-PIC  rtc
> >  11:      77842          XT-PIC  usb-uhci, usb-uhci, usb-uhci, eth0, 
> > wlan0, Ricoh Co Ltd RL5c476 II, Ricoh Co Ltd RL5c476 II (#2)
> >  12:     360259          XT-PIC  PS/2 Mouse
> >  14:      85559          XT-PIC  ide0
> > NMI:          0 
> > ERR:          0
> > 
> > 
> > Is there any reason a BIOS would do this?
> 
> The motherboard is a lousy design.    Only vary rarely
> have I not seen the basic irq assignments come down to traces
> on the motherboard.

what's worse is the PIR table claims that lots more interrupts are 
available. Sad, really.

ron




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