linux-kernel - Re: [regression, bisected] adb trackpad disappears after suspend to ram

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Message-Id: <1243918164.5308.23.camel@pasglop>
Date:	Tue, 02 Jun 2009 14:49:24 +1000
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Jan Scholz <scholz@...s.uni-frankfurt.de>,
	Paul Mackerras <paulus@...ba.org>, Ingo Molnar <mingo@...e.hu>,
	linux-kernel@...r.kernel.org, Adrian Bunk <bunk@...nel.org>,
	pm list <linux-pm@...ts.linux-foundation.org>
Subject: Re: [regression, bisected] adb trackpad disappears after suspend
 to ram

> So, it seems we lose and interrupt during resume and that confuses the
> ADB controller driver or something like this.  Do you use the keyboard or
> the trackpad as a wake-up device?
> 
> Please additionally try to go back to the original code, put
> 'sleepy_trackpad = 1' at the beginning of do_adb_reset_bus() in
> drivers/macintosh/adb.c and see if the problem is reproducible with that.

Well, the ADB controller is also the PMU (drivers/macintosh/via-pmu.c)
which is also the system controller, handles the actual sleep state,
etc... :-)

That code is a bit itchy around the edges. I'm not sure it would have
lost an interrupt, that sounds more like losing an IRQ would have broken
it completely but it's not -impossible- (especially if it's the external
GPIO or CB1 interrupt that notifies of an incoming ADB message).

I haven't managed to reproduce the problem yet here though. I'll see if
I can with a titanium powerbook I have somewhere in storage that might
be a bit closer to your machine than the wallstreet powerbook I've been
using to test at work :-) My other powerbook test machine uses a USB
trackpad. 

Cheers,
Ben.

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