On Mon, Aug 08, 2011 at 10:37:03PM +0200, Rafael J. Wysocki wrote: > On Monday, August 08, 2011, Yanmin Zhang wrote: > > On Fri, 2011-08-05 at 21:20 +0200, Rafael J. Wysocki wrote: > > > On Friday, August 05, 2011, Yanmin Zhang wrote: > > > > On Fri, 2011-08-05 at 09:57 +0800, Liu, ShuoX wrote: > > > > > > On Thursday, August 04, 2011, Greg KH wrote: > > > > > > > On Thu, Aug 04, 2011 at 01:13:38PM +0800, Liu, ShuoX wrote: > > > > > > > > >From a906b0b5b4ff3414ceb9fc7a69a3d7c9d66e46b1 Mon Sep 17 > > > > > > 00:00:00 2001 > > > > > > > > From: ShuoX Liu <shuox.liu@xxxxxxxxx> > > > > > > > > Date: Thu, 28 Jul 2011 10:54:22 +0800 > > > > > > > > Subject: [PATCH] PM: add statistics sysfs file for suspend to ram. > > > > > > > > > > > > > > What's this stuff here for? That's not needed (hint, I would have to > > > > > > > edit it out by hand to be able to apply this patch.) > > > > > > > > > > > > > > Thanks for resending a version that passes checkpatch.pl and could be > > > > > > > applied, but all of my previous comments still stand. This patch, as > > > > > > > is, is totally unacceptable. > > > > > > > > > > > > Agreed, plus I'd like to know the motivation behind it. That is, we have > > > > > > quite a few debug facilities in that code, so why are they insufficient? > > > > Thanks Greg, Rafael. We are changing the patch based on your comments. > > > > > > > > > > > > > > Some explanation from Yanmin, > > > > > "We are enabling power features on Medfield. Some testers and developers > > > > > complain they don't know if system tries suspend-2-ram, and what device > > > > > fails to suspend. They need such info for a quick check. If turning on > > > > > CONFIG_PM_DEBUG, we get too much info and testers need recompile > > > > > the system. > > > > Comparing with PC/notebook, a mobile enters/exits suspend-2-ram (we call it s3 on > > > > Medfield) far more frequently. If it can't enter suspend-2-ram in time, the power > > > > might be used up soon. > > > > > > > > We often find sometimes, a device suspend fails. Then, system retries s3 over > > > > and over again. As display is off, testers/developers don't know what happens. > > > > Teh system > > > > > > > > With the patch, we could know what the bad device is. > > > > > > > > The patch doesn't hurt performance as it's just statistics collector. > > > > > > > > CONFIG_PM_DEBUG is very useful for finer investigation about what happens behind. What > > > > we provide by the patch is to analyze the issues quickly, even by an ordinary tester. > > > > > > Well, what about using dynamic debug? > > Thanks for the nice pointer. I checked dynamic debug. It's really a good debug tool. > > With the dynamic debug: > > 1) user need write a user space parser to process the syslog output; > > 2) Our testing scenario is we leave the mobile for at least hours. Then, check its status. > > No serial console available during the testing. One is because console would be suspended, > > and the other is serial console connecting with spi or HSU devices would consume power. These > > devices are powered off at suspend-2-ram. > > > > Below is an example output of the statistics from my mobile (we are changing the output > > from sysfs to debugfs now): > > #adb shell cat /sys/power/suspend_stats > > success: 5 > > fail: 1 > > failed_freeze: 0 > > failed_prepare: 0 > > failed_suspend: 1 > > failed_suspend_noirq: 0 > > failed_resume: 0 > > failed_resume_noirq: 0 > > failed_devs: > > last_failed: alarm > > OK, I see. Greg, what do you think? Files in debugfs like this are fine with me. If you think the information is valid, and useful to people, I have no objection to the patch. thanks, greg k-h _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
