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

['Greg Kroah-Hartman' <gregkh@linuxfoundation.org>]

On Wed, Mar 02, 2022 at 08:00:14PM +0900, �念��/TV S/W Lab(VD)/Staff Engineer/�Ｚ���� wrote:
> > -----Original Message-----
> > From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Sent: Wednesday, March 2, 2022 4:58 PM
> > To: Youngjin Jang <yj84.jang@samsung.com>
> > Cc: Rafael J. Wysocki <rafael@kernel.org>; Pavel Machek <pavel@ucw.cz>;
> > Len Brown <len.brown@intel.com>; Bjorn Helgaas <bhelgaas@google.com>;
> > linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org; linux-
> > pci@vger.kernel.org; linux-acpi@vger.kernel.org; linux-
> usb@vger.kernel.org;
> > js07.lee@samsung.com
> > 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@samsung.com>
> > >
> > > 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@samsung.com>
> > > ---
> > >  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.

Why does that matter?  Fix them all to use the struct device pointer and
then they will be properly unified with the rest of the kernel log
infrastructure.

thanks,

greg k-h