Q on High level interrupt??

Question

we're porting our driver for our PCI board from NT to Solaris. When I load my driver, it shows it was assigned a hi_level interrupt in the attach() routine. If I try to get block cookie or register the ISR for this "hi_level" interrupt, the OS complains my device at IPL 12 conflicts with other device at IRQ 5 IPL 1..
so I have to add
interrupt-priorities=9;
in my driver.conf file to force it to use low level IPL.
I don't think there's hardware problem on our board since they're working fine under NT. My questions are
1. Why OS assign me a high level interrupt by default?
2. Am I allowed to use the hi level interrupt?
3. how to register a hi level interrupt?
Thanks alot.

Answer 1

Yes, solaris (x86 only) contains something like the following
routine to assign IPLs to pci devices:
int pci_devclass_to_ipl(int pci_devclass)
switch ((pci_devclass & 0xff0000) >> 16) {
default:
case PCI_CLASS_NONE: /* class code for pre-2.0 devices */
return 1;
case PCI_CLASS_MASS: /* Mass storage Controller class */
return 5;
case PCI_CLASS_NET: /* Network Controller class */
return 6;
case PCI_CLASS_DISPLAY: /* Display Controller class */
return 9;
case PCI_CLASS_MM: /* Multimedia Controller class */
case PCI_CLASS_MEM: /* Memory Controller class */
case PCI_CLASS_BRIDGE: /* Bridge Controller class */
return 12;
Don't know why sun has deciced that multimedia, memory
and bridge pci controllers must have an IPL 12 (= hi level
interrupt). The solution is indeed to add an
"interrupt-priorities=9;" line to your driver's .conf file to work
around this problem and get rid of the hilevel interrrupt.
My audio driver's (->multimedia) attach routine verifies that
the interrupt-priorities line is in use by making sure the
device is not registered for a hilevel interrupt, like this:
xxx_attach(...)
* Make sure we're not using a high level interrupt handler.
if (ddi_intr_hilevel(dip, 0)) {
cmn_err(CE_NOTE, "Driver does not support high level interrupt.");
cmn_err(CE_NOTE, "You should probably add 'interrupt-priorities=9;' to xxx.conf");
return DDI_FAILURE;