Messages in this thread | | | Subject | IO-APIC IRQs strange? (was Re: linux 2.1.98 sound timeouts) | From | Michael Poole <> | Date | 27 Apr 1998 23:01:22 -0400 |
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Michael Poole <poole@graviton.res.cmu.edu> writes:
> I'm seeing the same thing, and have been for a while, with my sound > card as well -- however, it gives the time out error every time an app > tries to use the wave output functions, and all I hear are quiet clicks.
After a patch from Artur Skawina that "should" have better supported my sound card didn't give any better results, I did a bit more digging. It turned up a very surprising result -- /proc/interrupts doesn't list all the interactions between IRQs and interrupt handlers that I was expecting, and this meant that I had been looking in entirely the wrong place for problems.
I discovered the discrepancy by booting back to 2.0.33, where I fully expected sound to work -- after all, it had worked before. However, it did not -- the ad1848 driver failed the IRQ10 test, which is where my (non-PNP) sound card lives. So I looked in /proc/interrupts, and it revealed said that my aic7xxx and Intel EEPro100 were on IRQ 10. Under 2.1.x, these were listed under IRQ 19 -- so I had assumed there was no conflict. I was wrong. After going into the BIOS and listing IRQ 10 (and a number of others, after trial and error) as being used by ISA peripherals, 2.0.33 reported the SCSI and NIC being on IRQ 14, and sound worked again -- both in 2.0.33 and 2.1.97.
So this raises a question in my mind: Why were the SCSI and network cards causing interference, apparently slurping away the interrupts which "should" have been received by the sound card driver? I understand that it was a misconfiguration on my part in the first place, but I didn't guess it until today because guessing was virtually all I could do under the 2.1 kernels. Would it be somehow possible to discover, if not rectify, this kind of occurence? I am willing and able to test patches to diagnose or to try to fix this, if any experienced kernel hackers are interested.
- Michael
P.S.: the Sound Galaxy driver from Artur Skawina is in good working order, now that the other problems have been fixed.
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