linux-kernel - Re: [linux-pm] "i8042: Can't reactivate AUX port" after s2ram on 3.4-rc2

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Date:	Fri, 13 Apr 2012 22:19:22 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Mikko Vinni <mmvinni@...oo.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Allen Kay <allen.m.kay@...el.com>,
	Jean Guyader <jean.guyader@...citrix.com>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Subject: Re: [linux-pm] "i8042: Can't reactivate AUX port" after s2ram on 3.4-rc2

On Friday, April 13, 2012, Mikko Vinni wrote:
> From: Rafael J. Wysocki:
> 
> > On Friday, April 13, 2012, Mikko Vinni wrote:
> >>  Bug report:
> >>     https://bugzilla.kernel.org/show_bug.cgi?id=43099
> >> 
> >>  Briefly:
> >> 
> >>  After s2ram the touchpad on a HP dv5 laptop doesn't work anymore.
> >> 
> >>  dmesg contains this about the touchpad
> >>  Apr 11 18:00:05 koni kernel: i8042: Can't write CTR while closing AUX 
> > port
> >>  Apr 11 18:00:08 koni kernel: i8042: Can't reactivate AUX port
> >> 
> >> 
> >>  Full log in bugzilla with PCI and i8042 debug turned on.
> >> 
> >>  Bisected to:
> >> 
> >>  commit 26f41062f28de65e11d3cf353e52d0be73442be1
> >>  Author: Kay, Allen M <allen.m.kay@...el.com>
> >>  Date:   Thu Jan 26 10:25:53 2012 -0800
> >> 
> >>      PCI: check for pci bar restore completion and retry
> >>     
> >>      On some OEM systems, pci_restore_state() is called while FLR has not 
> > yet
> >>      completed.  As a result, PCI BAR register restore is not successful.  
> > This fix
> >>      reads back the restored value and compares it with saved value and 
> > re-tries 10
> >>      times before giving up.
> > 
> > Does reverting the above commit on top of the current Linus' tree fix the
> > problem for you?
> 
> 
> It does (at least with the tree from yesterday, 4166fb64593514ad920b7dbd290e0a934b37d24a).

OK, thanks.

Please change that dev_dbg() in pci_restore_state() into dev_info()
and see how many times it gets printed with the commit applied (not reverted).

[Margin note: I think it would make more sense to read the value from
the register _after_ and not before the waiting and I'm not exactly sure why
msleep() is not used.]

Thanks,
Rafael
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