Messages in this thread | | | Subject | Re: [PATCH 1/2] PM: use dpm_run_callback in device_prepare | From | Yanmin Zhang <> | Date | Sat, 08 Jun 2013 09:21:52 +0800 |
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On Fri, 2013-06-07 at 18:15 -0700, Greg KH wrote: > On Sat, Jun 08, 2013 at 08:43:55AM +0800, Yanmin Zhang wrote: > > On Fri, 2013-06-07 at 10:37 -0700, Greg KH wrote: > > > On Fri, Jun 07, 2013 at 04:20:31PM +0800, shuox.liu@intel.com wrote: > > > > From: ShuoX Liu <shuox.liu@intel.com> > > > > > > > > dpm_run_callback could show more debug info around prepare stage. > > > > > > Why? Who needs this? What problem does it solve? > > > > > > Without answers to this, why would you expect us to accept such a > > > change? > > It's to provide more debug info and developers can quickly find what > > prepare/complete callback consumes too much time. > > What exact debug info is this providing, and why wouldn't you say all of > this in the original changelog information? Thanks for the reminder.
Below are examples, after applying the patches. We can see clearly how much time every device prepare callback consumes.
[ 600.384779] sr 1:0:0:0: preparing bus suspend [ 600.384780] call 1:0:0:0+ returned 0 after 2 usecs [ 600.384785] calling 2-1+ @ 2556, parent: usb2 [ 600.384788] usb 2-1: preparing type suspend [ 600.384789] call 2-1+ returned 0 after 2 usecs [ 600.384794] calling 1-1.1+ @ 2556, parent: 1-1 [ 600.384797] usb 1-1.1: preparing type suspend [ 600.384799] call 1-1.1+ returned 0 after 2 usecs [ 600.384802] calling 1-1.3+ @ 2556, parent: 1-1 [ 600.384804] usb 1-1.3: preparing type suspend [ 600.384805] call 1-1.3+ returned 0 after 2 usecs [ 600.384809] calling 1-1.4+ @ 2556, parent: 1-1 [ 600.384811] usb 1-1.4: preparing type suspend [ 600.384813] call 1-1.4+ returned 0 after 2 usecs [ 600.384816] calling 1-1.5+ @ 2556, parent: 1-1 [ 600.384819] usb 1-1.5: preparing type suspend, may wakeup [ 600.384820] call 1-1.5+ returned 0 after 2 usecs [ 600.384823] calling 1-1.4.1+ @ 2556, parent: 1-1.4 [ 600.384825] usb 1-1.4.1: preparing type suspend [ 600.384827] call 1-1.4.1+ returned 0 after 2 usecs [ 600.384829] calling 1-1.4.2+ @ 2556, parent: 1-1.4 [ 600.384831] usb 1-1.4.2: preparing type suspend [ 600.384833] call 1-1.4.2+ returned 0 after 2 usecs [ 600.384865] PM: prepare suspend of devices complete after 0.471 msecs
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