lkml.org 
[lkml]   [2004]   [May]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Is it possible to implement interrupt time printk's reliably?
--- 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




__________________________________
Do you Yahoo!?
Win a $20,000 Career Makeover at Yahoo! HotJobs
http://hotjobs.sweepstakes.yahoo.com/careermakeover
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:02    [W:0.035 / U:1.348 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site