linux-kernel - Nokia N900 retention mode in v4.6, camera buttons fun

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Date:	Tue, 12 Apr 2016 14:16:58 +0200
From:	Pavel Machek <pavel@....cz>
To:	Tony Lindgren <tony@...mide.com>
Cc:	pali.rohar@...il.com, sre@...nel.org,
	kernel list <linux-kernel@...r.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	linux-omap@...r.kernel.org, khilman@...nel.org,
	aaro.koskinen@....fi, ivo.g.dimitrov.75@...il.com,
	patrikbachan@...il.com, serge@...lyn.com,
	Tomi Valkeinen <tomi.valkeinen@...com>
Subject: Nokia N900 retention mode in v4.6, camera buttons fun

Hi!

> > > Do you think you could try with my config?
> 
> Yeah disabling lockdep by removing PROVE_LOCKING from omap2plus_defconfig
> makes n900 LCD work for me again. Not getting any lockdep warnings
> during boot with lockdep enabled though. So basically the following
> patch makes LCD work on n900 with omap2plus_defconfig.

Good, at least it is consistent.

> > Ok, it works now. I was doing tests in daylight so it was poorly
> > visible. The right part of keyboard stays lit (but that's expected
> > AFAICT), but the left part blinks.
> 
> During idle, both should go off and are doing so for me. Both LEDs off
> indicates off mode, left LED off is for retention mode. So you still
> have something blocking off mode, maybe check:
> 
> echo 1 > /sys/kernel/debug/pm_debug/enable_off_mode

What is the power difference between retention and off? I'm now down
to cca 25mA, which should be around 50 hours standby time. Not ideal,
but should be usable.

In the meantime, I found what is causing the rention mode to break for
me: CONFIG_HSI (aka wireless modem support). With HSI off, it seems to work.

I still get problems with the camera button, in config similar to
defconfig.  For some reason, I'm even getting (autorepeating) ^@ on
console. As long as I hold camera button down, I even get it into off
mode for brief period.

Best regards,
								Pavel
								
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html