RE: [PATCH] PM: Add device name to suspend_report_result()

[장영진/TV S/W Lab(VD)/Staff Engineer/삼성전자]

> -----Original Message-----
> From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Sent: Wednesday, March 2, 2022 4:58 PM
> To: Youngjin Jang <yj84.jang@xxxxxxxxxxx>
> Cc: Rafael J. Wysocki <rafael@xxxxxxxxxx>; Pavel Machek <pavel@xxxxxx>;
> Len Brown <len.brown@xxxxxxxxx>; Bjorn Helgaas <bhelgaas@xxxxxxxxxx>;
> linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> pci@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; linux-
usb@xxxxxxxxxxxxxxx;
> js07.lee@xxxxxxxxxxx
> Subject: Re: [PATCH] PM: Add device name to suspend_report_result()
> 
> On Wed, Mar 02, 2022 at 03:49:17PM +0900, Youngjin Jang wrote:
> > From: "yj84.jang" <yj84.jang@xxxxxxxxxxx>
> >
> > currently, suspend_report_result() prints only function information.
> > If any driver uses common pm function, nobody knows who called failed
> > function exactly.
> >
> > So, device information is needed to recognize specific wrong driver.
> >
> > e.g.)
> > PM: dpm_run_callback(): pm_generic_suspend+0x0/0x48 returns 0
> > PM: dpm_run_callback(): platform_pm_suspend+0x0/0x68 returns 0 after
> > patch,
> > PM: dpm_run_callback(): pm_generic_suspend+0x0/0x48 (amba) returns 0
> > PM: dpm_run_callback(): platform_pm_suspend+0x0/0x68 (armv7-pmu)
> > returns 0
> >
> > Signed-off-by: yj84.jang <yj84.jang@xxxxxxxxxxx>
> > ---
> >  drivers/base/power/main.c  | 10 +++++-----
> >  drivers/pci/pci-driver.c   | 14 +++++++-------
> >  drivers/pnp/driver.c       |  2 +-
> >  drivers/usb/core/hcd-pci.c |  4 ++--
> >  include/linux/pm.h         |  8 ++++----
> >  5 files changed, 19 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> > index 04ea92c..a762fe8 100644
> > --- a/drivers/base/power/main.c
> > +++ b/drivers/base/power/main.c
> > @@ -485,7 +485,7 @@ static int dpm_run_callback(pm_callback_t cb, struct
> device *dev,
> >  	trace_device_pm_callback_start(dev, info, state.event);
> >  	error = cb(dev);
> >  	trace_device_pm_callback_end(dev, error);
> > -	suspend_report_result(cb, error);
> > +	suspend_report_result(dev, cb, error);
> >
> >  	initcall_debug_report(dev, calltime, cb, error);
> >
> > @@ -1568,7 +1568,7 @@ static int legacy_suspend(struct device *dev,
> pm_message_t state,
> >  	trace_device_pm_callback_start(dev, info, state.event);
> >  	error = cb(dev, state);
> >  	trace_device_pm_callback_end(dev, error);
> > -	suspend_report_result(cb, error);
> > +	suspend_report_result(dev, cb, error);
> >
> >  	initcall_debug_report(dev, calltime, cb, error);
> >
> > @@ -1855,7 +1855,7 @@ static int device_prepare(struct device *dev,
> pm_message_t state)
> >  	device_unlock(dev);
> >
> >  	if (ret < 0) {
> > -		suspend_report_result(callback, ret);
> > +		suspend_report_result(dev, callback, ret);
> >  		pm_runtime_put(dev);
> >  		return ret;
> >  	}
> > @@ -1960,10 +1960,10 @@ int dpm_suspend_start(pm_message_t state)  }
> > EXPORT_SYMBOL_GPL(dpm_suspend_start);
> >
> > -void __suspend_report_result(const char *function, void *fn, int ret)
> > +void __suspend_report_result(const char *function, struct device
> > +*dev, void *fn, int ret)
> >  {
> >  	if (ret)
> > -		pr_err("%s(): %pS returns %d\n", function, fn, ret);
> > +		pr_err("%s(): %pS (%s) returns %d\n", function, fn,
> > +dev_driver_string(dev), ret);
> 
> If you have a struct device, please use dev_err().
> 
> thanks,
> 
> greg k-h

Hello,
Thanks for your review.

I think dev_err() is nice option, but we can see a minor issue.
Prefix log "PM: " would be lost, If I use dev_err() in this context.
As you know, all logs in power management include "PM :" prefix.

So, I think pr_err() with detail information would be better than dev_err().
- PM: amba 1740000.etm: dpm_run_callback(): pm_generic_resume+0x0/0x48
returns 0