From: Jon Smirl <jonsmirl@yahoo.com>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, keithp@keithp.com
Subject: Re: Is it possible to implement interrupt time printk's reliably?
Date: Fri, 7 May 2004 12:26:50 -0700 (PDT) [thread overview]
Message-ID: <20040507192650.95994.qmail@web14926.mail.yahoo.com> (raw)
In-Reply-To: <20040507121319.6939b391.akpm@osdl.org>
--- Andrew Morton <akpm@osdl.org> wrote:
> Jon Smirl <jonsmirl@yahoo.com> wrote:
> >
> > > 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?
> >
>
> Nope. If printk finds the semaphore to be held it queues up the characters
> and returns without printing them. The console_sem-holding process will
> print the newly buffered characters before releasing the semaphore.
Is this solution sufficient for kernel developers wanting to use printk from
interrupt handlers? I've gotten negative feedback from Linus when I suggested
queuing them before.
=====
Jon Smirl
jonsmirl@yahoo.com
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next prev parent reply other threads:[~2004-05-07 20:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-07 2:52 Jon Smirl
2004-05-07 5:17 ` Andrew Morton
2004-05-07 13:34 ` Jon Smirl
2004-05-07 19:13 ` Andrew Morton
2004-05-07 19:26 ` Jon Smirl [this message]
2004-05-07 20:01 ` Andrew Morton
2004-05-09 16:33 ` Jon Smirl
2004-05-10 21:55 ` James Simmons
2004-05-10 22:22 ` Jon Smirl
2004-05-11 0:23 ` James Simmons
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