----- Original Message ----- From: "Scott Garman" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, July 25, 2002 5:30 PM Subject: Fighting with IRQs.
> I would really like to learn more about how IRQ and IO assignment is > done by BIOS and Linux, if anyone could point me to some good > documentation. My second choice would be to get some quick enlightenment > as to what I am doing wrong - it's kind of hard to decide which Ogg > Vorbis quality level to encode to when I can't do my audio testing > without getting beeps and clicks! :) > Well, you could start by reading your Motherboard Manual's BIOS setup section. While mostly in broken English, they can contain some useful information. For example, my Award BIOS for a VIA 694X chipset lists something called "Reset Configuration Data" which causes all the IRQs to be reallocated on boot up by the ESCD (Extended System Configuration Data) program in the BIOS. If I were to disable this setting, I could manually assign all my IRQs based on PCI slots (or ISA slots if I had any.) If your IRQs are piling up using the ESCD BIOS assignment, try turning this feature off and manually assigning your IRQs (or at least the ones you want to force.) The way resources get allocated (very basically) is this: IF you have your PNP OS setting set to YES, the BIOS will only initialize those devices required for booting (VGA, SCSI, IDE.) The BIOS leaves the rest of the cards alone, assuming that your PnP OS will initialize them. Whether you should have this set to YES or not will depend on your specific Linux distribution. I believe the newer 2.4.x kernels do a pretty good job of allocating resources. Of course, if you have an older distro or an older (read: imperfect) implementation of the PnP BIOS, you should probably keep this disabled. If you have the "Reset Configuration Data" setting set to ENABLED, the BIOS will use the ESCD program to reallocate your resources on every boot. This is evidenced by the ESCD update success message you see on bootup. Normally you do not need to do this on every boot, as the cards' flash memories will retain their settings across most normal power cycles. (I think the cards reset this data and ask for configuration if they detect they have been moved to another slot, but don't quote me on that.) My motherboard manual recommends leaving this at DISABLED unless I have created a conflict that prevents booting the system. So that's what I do. :o) Then most BIOSes have a section that allows you to set the assignment of each IRQ, and sometimes the DMA channels too. The usual settings are AUTO(ESCD) and MANUAL. When resources are controlled manually, I think you need to tell the BIOS which bus (ISA OR PCI) the resource belongs to. Anything else I say at this point will fall into the realm of speculation, because I've just about exhausted my knowledge on the subject, so I'll stop here :o) Rich Cloutier President, C*O SYSTEM SUPPORT SERVICES www.sysupport.com ***************************************************************** To unsubscribe from this list, send mail to [EMAIL PROTECTED] with the text 'unsubscribe gnhlug' in the message body. *****************************************************************
