From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Michael Hanselmann <linux-kernel@hansmi.ch>
Cc: linuxppc-dev@ozlabs.org, johannes@sipsolutions.net,
linux-kernel@killerfox.forkbomb.ch
Subject: Re: [PATCH] SMU LED driver
Date: Mon, 15 Jan 2007 08:48:59 +1100 [thread overview]
Message-ID: <1168811339.4803.23.camel@localhost.localdomain> (raw)
In-Reply-To: <20070114133119.GA22354@hansmi.ch>
On Sun, 2007-01-14 at 14:31 +0100, Michael Hanselmann wrote:
> On Mon, Jan 08, 2007 at 12:02:45PM +1100, Benjamin Herrenschmidt wrote:
> > Just have 1 request allocated once for all. Then, have a global set to
> > what status you want the LED at. Once the completion of any request
> > arrives, if the new status is different from what you want, send a new
> > one to fix it up :-)
>
> Implemented that. See below.
>
> There's a race condition between setting the LED value and unloading the
> module. smu_led_exit can't return an error. Is it possible to prevent
> unloading the module while an SMU request is still running, and if yes,
> how?
No, you have to deal with it in the unload. You can for example wait for
the SMU request to complete after setting wanted to -1, that sort of
thing.
Also, use spin_lock_irqsave/restore or you'll deadlock if the SMU
completion interrupt happens to interrupt your request function.
Ben.
next prev parent reply other threads:[~2007-01-14 21:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-24 11:23 [PATCH] SMU LED driver Michael Hanselmann
2006-12-25 21:25 ` Benjamin Herrenschmidt
2006-12-26 22:38 ` Johannes Berg
2007-01-06 21:19 ` Michael Hanselmann
2007-01-08 1:02 ` Benjamin Herrenschmidt
2007-01-14 13:31 ` Michael Hanselmann
2007-01-14 21:48 ` Benjamin Herrenschmidt [this message]
2007-01-15 0:26 ` Michael Hanselmann
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