Date:	Tue, 02 Jun 2009 00:34:26 +0200
From:	Jan Scholz <scholz@...s.uni-frankfurt.de>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Jan Scholz <scholz@...s.uni-frankfurt.de>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	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

"Rafael J. Wysocki" <rjw@...k.pl> writes:

> On Monday 01 June 2009, Jan Scholz wrote:
>> "Rafael J. Wysocki" <rjw@...k.pl> writes:
>> 
>> > On Friday 29 May 2009, Jan Scholz wrote:
>> >> Benjamin Herrenschmidt <benh@...nel.crashing.org> writes:
>> >> 
>> >> >> We are too late in the cycle to revert this commit and it really is needed to
>> >> >> fix a more serious issue.  Nevertheless knowing that it caused the problem to
>> >> >> appear on your system is also important.
>> >> >> 
>> >> >> Ben, do you have an idea what may be going on here?  Does __disable_irq() mask
>> >> >> the interrupt on this platform?
>> >> >
>> >> > I suppose so :-) I'll have to check what's going on, it's not
>> >> > immediately clear to me.
>> >> >
>> >> > Cheers,
>> >> > Ben.
>> >> >
>> >> >> 
>> >> >> I'd like to see a boot log, preferably containing a suspend-resume in which
>> >> >> the problem was reproduced.
>> >> 
>> >> Here is a log from booting, through several suspend cycles, until the
>> >> trackpad disappeared. The first few suspends were done while X was
>> >> running but from the console. As you can tell from lines like
>> >>    May 28 23:51:26 [kernel] adb devices: [2]: 2 c4 [3]: 3 1 [7]: 7 1f
>> >> the trackpad was still present. The last suspend was done from within X,
>> >> here the trackpad did not make it.
>> >>    May 28 23:58:09 [kernel] adb devices: [2]: 2 c4 [7]: 7 1f
>> >> However, there have been cases, although not in this log, were the
>> >> trackpad has been alive even when suspending from within X.
>> >
>> > This means the problem is probably timing-related.
>> >
>> > Can you please try to comment out suspend_device_irqs() and
>> > resume_device_irqs()  in drivers/base/power/main.c and see if that changes
>> > anything?  It's not entirely safe (well, that's why the calls are there after
>> > all), but hopefully the box won't hang during this test.
>> >
>> 
>> Tried that against v2.6.30-rc7 and it seems to fix the issue. I did ~10
>> suspend-resume cycles from the console (which worked just like before)
>> and ~20 cycles from within X and the trackpad is still alive.
>
> 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?

I do the wakeup by pressing keys on the keyboard. I'd try wakeup via the
trackpad's button, but I have no idea how to activate that.

> 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.

Tried this, but it does not help.

What I haven't noticed before is, that even if the trackpad already
disappeared, an additional suspend-resume cycle from the console brought
it back to life every time. Sometimes this worked from within X as well,
just not with such a high probability as from the console.
However, this is independent from 'sleepy_trackpad = 1'. 

Best,
   Jan
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