10 Oct
2003
10 Oct
'03
7:25 a.m.
Clemens Ladisch wrote:
wes schreiner wrote:
Well there we go, so it's back to juggling cards in PCI slots and
switching motherboards. I can report that irqtune does indeed change the
interrupt priority though, using kernel 2.4.21. That might help someone.
wes
The support for using lspci/setpci is in all 2.4.x
kernels I think, but
it doesn't always do what you want. I have a Zoran 36057 video capture
device sitting on IRQ 10, same as my sound card. IRQ 9 is unused (no
ACPI), so I just tried "setpci -v -s 03:09.0 INTERRUPT_LINE=09" to
change its IRQ. lspci -v still says it is at IRQ 10, but lspci -b -v
says it is at IRQ 9. Which is it? OK, I modprobe zr36067 and the module
loads, and now both lspci -v and lspci -v -b agree that the Zoran chip
is at IRQ 10, so nothing changed.
The interrupt_line register doesn't affect the card in any way, it's
there for information purposes only. The BIOS sets this register so
that drivers know which interrupt to use.
To change the interrupt routing, you have to reprogram some registers
of the PCI controller (starting at 60h in Intel's ICHx southbridges
IIRC, but read Intel's datasheet first). And I don't know if the
kernel is able to realize that the interrupt has changed.
HTH
Clemens