It turns out that as soon as I insert the module I get continuous
interrupts calling drivers/usb/uhci.c:uhci_interrupt() on the
PCI shared IRQ 11.
I've downloaded the 82371AB, PIIX4, UHCI, USB specs and tried
various hacks to uhci.c but cannot get it to stop the interrupts
which makes me feel that it is perhaps one of the other PCI devices
that is generating the interrupt and not the USB controller.
So this is where I'm stuck. I boot 2.3.11 in single user mode,
CTRL-ALT-SYSRQ-SU to mount / read-only to stop the fsck when it
crashes, insert usb-uhci and get a print out of some of my
debug messages. So now I know that nothing else has been loaded
that might share the interrupt and yet the interrupts are still
generated.
If I have nothing connected to the USB port my first interrupt
has a status from inw(io_addr+USBSTS) of 0x20, i.e HC halted
and so does every subsequent one. If I add the following code
to get the HC running again then all subsequent interrupts
have status 0, i.e. nothing generated the interrupt...
if (status == 0x20)
{
outw(USBCMD_RS|USBCMD_CF|USBCMD_MAXP, io_addr+USBCMD);
}
So back to the docs and find out about PCI steering. The Tosh
has the following PCI devices on IRQ 11:
Neomagic 256AV: Pin A->IRQ 11
USB: Pin D->IRQ 11
Lucent HDSP1645 (winmodem): Pin A->IRQ 11
ESS Maestro 2E: Pin A->IRQ 11 (hmmm, I did get the opensound driver...)
C-Cube multimedia something: Pin A->IRQ 11
I cannot figure out how the IRQ handler is supposed to determine
which device generated the interrupt, and worse, if some device
generated the interrupt but the handler isn't installed, how
do the other handlers ignore it?
Nor can I find out how to steer the USB IRQ to another interrupt.
I'm assuming that this is a solved problem. The BIOS doesn't have
any way to specify this.
Any ideas?
Paul
-- paul666 @mailandnews com
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