From: Johannes Berg <johannes@sipsolutions.net>
To: benh@kernel.crashing.org
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
linuxppc-dev list <linuxppc-dev@ozlabs.org>,
linux-pm <linux-pm@lists.osdl.org>, ralf <ralf@linux-mips.org>
Subject: Re: apm_emulation regression
Date: Wed, 12 Dec 2007 19:03:07 +0100 [thread overview]
Message-ID: <1197482587.6558.145.camel@johannes.berg> (raw)
In-Reply-To: <1197427530.8385.59.camel@pasglop>
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On Wed, 2007-12-12 at 13:45 +1100, Benjamin Herrenschmidt wrote:
> I only just noticed a huge regression that was introduced when we moved
> PowerPC to the generic APM emulation code instead of our own. I'm in
> large part to blame since I acked the patch...
>
> Basically, what we lost is the mechanism for notifying user applications
> and waiting for their ACK before proceeding to system suspend. The new
> generic code will still do that ... only when the actual suspend request
> initiates from an APM suspend ioctl.
Indeed.
> For any other suspend (via our private PMU ioctl or via the sysfs
> interface), userspace will -not- be notified.
Right.
> That basically means X will break. That's why X broke on the latest
> ubuntu until I whacked some new scripts in them to force console
> switching, among other things. Possibly other apps that relied
> on /dev/apm_bios to be notified of system suspend/resume broke as well.
Ah. I guess I never noticed because I had the scripts to do console
switching all along.
> Now the question is that is it still work trying to fix it ? That would
> probably require APM emulation hooking at a fairly high level into the
> generic PM code to trigger the signaling & waiting of processes before
> freeze & device suspend among others...
Yeah, bit icky... but doable. Rafael, any ideas?
johannes
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next parent reply other threads:[~2007-12-12 18:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1197427530.8385.59.camel@pasglop>
2007-12-12 18:03 ` Johannes Berg [this message]
2007-12-13 11:40 ` apm_emulation regression Johannes Berg
2007-12-13 20:31 ` Benjamin Herrenschmidt
2007-12-14 0:10 ` Rafael J. Wysocki
2007-12-14 0:04 ` Benjamin Herrenschmidt
2007-12-14 0:05 ` Benjamin Herrenschmidt
2007-12-14 12:18 ` Johannes Berg
2007-12-15 0:20 ` Rafael J. Wysocki
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