Re: Is it possible to implement interrupt time printk's reliably?

[Andrew Morton]

Jon Smirl <jonsmirl@xxxxxxxxx> 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?

If you're in process context you can use acquire_console_sem(), which will
serialise against printk.

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