LinkSys EtherFast 10/100 LAN Card
Fri Nov 6 01:40:42 1998
On Thu, 5 Nov 1998, David Rose wrote:
>It turned out that enabling OS support of PnP didn't solve the problem
>altogether; it only postponed it. As soon as I'd added back in my
>modem card (which wanted--you guessed it--IRQ3), the LinkSys card
>went back to its old favorite, IRQ9, and stopped working again.
>Removing the modem card again didn't help; the LinkSys card had
>somehow decided it was happy at IRQ9 and wanted to stay there.
An old (2.1.120) Linux kernel had the following notice in it:
+ * - IRQ9 is broken on PIIX4 motherboards:
+ * "IRQ9 cannot be re-assigned"
+ * IRQ9 is not available to assign to
+ * ISA add-in cards because it is
+ * dedicated to the power
+ * management function of the PIIX4
+ * controller on the motherboard.
+ * This is true for other motherboards
+ * which use the 82371AB PIIX4
+ * component.
I don't remember what motherboard you had, but I suppose it's possible the
PIIX4 was asserting the interrupt since there isn't a Linux driver for it.
PCI sharing probably wouldn't work either since the tulip will always get
the interrupt and won't service it.
>It seems that my graphics adaptor card also wants to use IRQ9. Under
>Windows, the two can share the interrupt happily, but not so for some
>reason in Linux. Perhaps this is because of some problem with the
>graphics adaptor drivers? I know that my graphics support in Linux is
>far from complete, but it seems strange that this should have such a
>catastrophic effect on the IRQ sharing.
Look for an "ACPI" driver in the Windows system devices list.