Lennart Sorensen wrote: > On Sun, Feb 18, 2007 at 03:07:29PM +0100, Udo van den Heuvel wrote: >> How, based on what information, does Linux assign an IRQ to each card, >> plugged into the riser? >> How can one tweak/influence the irq routing? >> How can I make a dual riser card work so that both cards have a working >> interrupt? >> Or if stuff should work all by itself, what could be wrong? > > The PCI specifications cover how pci to pci bridges should work. > > My understanding (which is better of verified against the specs) is: [....] > The same rules apply behind a PCI bridge, so whatever INTA is on the > slot with the pci bridge chip, should make to INTA on slots 0, 4, 8, etc > behind the bridge, while INTB is seen as INTA on slots 1, 5, 9, etc.
FYI: My situation is a VIA Epia EN12000 with a TranquilPC dual PCI riser where only the Device Number can be changed. The kernel sees the two DVB cards in there as: saa7146: register extension 'budget_av'. ACPI: PCI Interrupt 0000:00:13.0[A] -> GSI 16 (level, low) -> IRQ 16 saa7146: found saa7146 @ mem f8c3e000 (revision 1, irq 16) (0x153b,0x1157). saa7146 (0): dma buffer size 192512 DVB: registering new adapter (Terratec Cinergy 1200 DVB-T). adapter failed MAC signature check encoded MAC from EEPROM was ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff KNC1-0: MAC addr = 00:0a:ac:01:d6:87 DVB: registering frontend 0 (Philips TDA10046H DVB-T)... budget-av: ci interface initialised. ACPI: PCI Interrupt 0000:00:14.0[A] -> GSI 17 (level, low) -> IRQ 20 saa7146: found saa7146 @ mem f8cb2000 (revision 1, irq 20) (0x153b,0x1155). saa7146 (1): dma buffer size 192512 DVB: registering new adapter (TerraTec Cinergy 1200 DVB-S). adapter failed MAC signature check encoded MAC from EEPROM was ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff sd 0:0:0:0: Attached scsi generic sg0 type 0 KNC1-1: MAC addr = 00:0a:ac:12:93:8d DVB: registering frontend 1 (ST STV0299 DVB-S)... budget-av: ci interface initialised. So IRQ 16 and 20. But when using the stock 2.6.20 kernel there is no communication with the DVB-T card (the frontend), so there is no /dev/dvb/* entry. This points to an IRQ problem. How can I find out the actual IRQ that the card is using? If it is different from what Linux thinks: how do I tell Linux? > On a PC, the BIOS is supposed to assign interrupts to devices based on > those rules, since that is how the hardware must be done according to > the PCI specifications. I set the BIOS for 'PnP OS installed'. Should I change that? > (....) Thanks for your response! Kind regards, Udo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/