Re: [PATCH] PM-Trace: add pm-trace support for suspending phase

From: Rafael J. Wysocki
Date: Thu Feb 12 2015 - 17:01:57 EST


On Thursday, February 12, 2015 12:48:06 PM Fu, Zhonghui wrote:
>
> On 2015/2/11 23:25, Rafael J. Wysocki wrote:
> > On Wednesday, February 11, 2015 10:43:13 PM Fu, Zhonghui wrote:
> >> From 2626594c03ca3b9884dd44073385c36f99a3651d Mon Sep 17 00:00:00 2001
> >> From: Zhonghui Fu <zhonghui.fu@xxxxxxxxxxxxxxx>
> >> Date: Wed, 11 Feb 2015 16:20:21 +0800
> >> Subject: [PATCH] PM-Trace: add pm-trace support for suspending phase
> > Can you please avoid putting the above header lines into your patches?
> >
> > The only one that may be necessary is the From: line, but that's only
> > needed if you submit from a different address.
> >
> > Also please don't send To: mailing lists. Use CC instead. In fact, there
> > should be *one* address in the To: field when you're submitting a patch:
> > The address of the maintainer you want to apply the patch for you.
> Thanks for your guidance, and I will re-send this patch.
>
> >
> >> Occasionally, the system can't come back up after suspend/resume
> >> due to problems of device suspending phase. This patch make
> >> PM_TRACE infrastructure cover device suspending phase of
> >> suspend/resume process, and the information in RTC can tell
> >> developers which device suspending function make system hang.
> > Do you have any examples of when this helped and no other debug methods did?
> >
> > It seems odd to me that no one has ever asked for this for several years and
> > now you need it.
> We ever run into some system hang during suspending some devices on BayTrail-T
> platform such as DMA, audio, etc. So, extending PM-Trace to suspend phase should
> be helpful.

Well, did you actually use this particular patch for debugging that?

Rafael

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