Messages in this thread | | | Date | Fri, 5 Nov 1999 10:01:24 -0500 | From | "Theodore Y. Ts'o" <> | Subject | Re: Common IRQ pitfall results in lockup. |
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Date: Fri, 5 Nov 1999 13:23:47 +0100 (MET) From: R.E.Wolff@BitWizard.nl (Rogier Wolff)
Alan, I'd like to discuss with you and Ted what we'll do about the 2.2 serial driver: Leave as is (please, no!), upgrade to Teds newest driver with PCI serial card support (with fix), or just a minimal fix.
I'm still working on fixing some problems with the serial console in my latest driver, so it's not ready for 2.2 yet. But I hope to have an updated serial driver (with some additional PCI cards supported) ready soon.
A client reports that this problem occurred (and that my fix fixed it), when his SCSI card was sharing the interrupt. The cards driver however isn't listed as "misbehaving", so I'm not so sure that the problem ONLY occurs when both drivers are "misbehaving". If that's the case, the bug isn't (in genetic terms) "recessive" (i.e. happens only when BOTH drivers misbehave) as my analysis would make you believe, but "dominant" (i.e. can happen when either driver misbehaves).
I'll fix the dev_id problem in request_irq, but my reading of how request_irq and free_irq works is that it finds the first matching dev_id, and free's it. So if only one driver is using a NULL irq, there shouldn't be a problem. If you think otherwise, could you do a bit more investigating? There may be something else that we're not seeing, and that makes me nervous.
(Also, note that until recently, the serial driver didn't allow IRQ sharing at all, so the 2.2 serial driver, which doesn't support PCI, shouldn't really be a problem except for PCMCIA cards, which were the only exeception to that rule to support multifunction serial/network cards, and none of the ethernet drivers are affected. So the current 2.2 serial driver shouldn't be causing any problems as far as I can tell.)
- Ted
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