Re: Possible suspend/resume regression in .32-rc?

From: Haojian Zhuang
Date: Mon Nov 02 2009 - 04:22:41 EST

On Sun, Nov 1, 2009 at 6:03 PM, Pavel Machek <pavel@xxxxxx> wrote:
>> Hi!
>> > > Is anyone using suspend/resume with a recent git mainline kernel on PXA
>> > > or other ARM embedded boards? My platform used to suspend and resume
>> > > just fine on 2.6.31 but now as I rebased it, it fails the resume part.
>> > >
>> > > Unfortunately, I can't bisect it as the platform is not mainline yet and
>> > > so I always have mandatory patches (without my platform won't do
>> > > anything) on top of the git repository. Which breaks the bisect logic.
>> > >
>> > > What puzzles me is that I see the current raising at wakeup time, so at
>> > > least the processor seems to resume, but I can't see any serial console
>> > > output, just like if the kernel crashed very early after wakeup.
>> > > 'no_console_suspend' didn't help either.
>> >
>> > Ok, got it. The culprit is commit d2c37068 ("[ARM] pxa: initialize
>> > default interrupt priority and use ICHP for IRQ handling"). Reverting it
>> > make suspend/resume work again on my board.
>> >
>> > Haojian, Eric, could you have a look at this?
>> Okay, patch is this one: I'll test reverting it shortly.
>> commit d2c37068429b29d6549cf3486fc84b836689e122
>> Author: Haojian Zhuang <haojian.zhuang@xxxxxxxxxxx>
>> Date:   Wed Aug 19 19:49:31 2009 +0800
>>     [ARM] pxa: initialize default interrupt priority and use ICHP for IRQ handling
>>     Signed-off-by: Haojian Zhuang <haojian.zhuang@xxxxxxxxxxx>
>>     Signed-off-by: Eric Miao <eric.y.miao@xxxxxxxxx>
> And yes, reverting it _does_ fix suspend on spitz.
>                                                                        Pavel

Em, it's not caused by the IRQ patch.

The kernel is blocked in resume path. When console is resumed, IRQ is
already disabled and system is blocked. Actually, IRQ shouldn't be
disabled at here. Up to now, I only find which patch will cause this
issue. But I can't find the best solution on it. The patch with issue
is pasted in below.

So this issue is only occused when console suspend is enabled. If you
enable no_console_suspend in command, you won't meet this issue. It
seems that it's caused by removing termios setting in
uart_resume_port() in the below patch. If I add these code back, the
issue doesn't occur any more.

Could you help to investigate this issue also?

By the way, the suggested quick test command is in below. If we tried
these commands for 20 times, the issue would occur. I only test it in
PXA silicon. I don't know the symptom on other silicons.
$ echo devices > /sys/power/pm_test
$ echo mem > /sys/power/state