Messages in this thread | | | Date | Fri, 7 May 2004 06:34:03 -0700 (PDT) | From | Jon Smirl <> | Subject | Re: Is it possible to implement interrupt time printk's reliably? |
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--- Andrew Morton <akpm@osdl.org> wrote: > Jon Smirl <jonsmirl@yahoo.com> wrote: > > > > Problem: > > 1) Some operations on graphics cards cannot be stopped once they are > started. > > It's not reasonable to turn interrupts off around these operations. > > 2) Kernel developers want console printk's to work from interrupt routines. > > > > How do you fix this situation? > > Really you should use spin_lock_irqsave() on some driver-private lock > around the operation. Why is it not reasonable to disable irq's? > Duration, presumably?
The operations take a while and would ruin latency. You might be copying 8MB of data.
> If you're in process context you can use acquire_console_sem(), which will > serialise against printk. >
Won't I deadlock if I have acquire_console_sem(), take an interrupt, and then a printk is issued from the interrupt handelr?
===== Jon Smirl jonsmirl@yahoo.com
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