[Intel-gfx] [PATCH v3] PCI / PM: tune down RPM suspend error message with EBUSY and EAGAIN retval

[Rafael J. Wysocki]

On Fri, Nov 27, 2015 at 7:17 PM, Imre Deak <imre.deak at intel.com> wrote:
> The runtime PM core doesn't treat EBUSY and EAGAIN retvals from the driver
> suspend hooks as errors, but they still show up as errors in dmesg. Tune
> them down.
>
> One problem caused by this was noticed by Daniel: the i915 driver
> returns EAGAIN to signal a temporary failure to suspend and as a request
> towards the RPM core for scheduling a suspend again. This is a normal
> event, but the resulting error message flags a breakage during the
> driver's automated testing which parses dmesg and picks up the error.
>
> v2:
> - fix compile breake when CONFIG_PM_SLEEP=n (0-day builder)
> v3:
> - instead of modifying the suspend_report_result() helper to disinguish
>   between the runtime and system suspend case, inline the error
>   printing, it's not used anywhere else (Rafael)
>
> Reported-by: Daniel Vetter <daniel.vetter at intel.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92992
> CC: Bjorn Helgaas <bhelgaas at google.com>
> CC: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/pci/pci-driver.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 4446fcb..67eb4ac 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -1146,9 +1146,20 @@ static int pci_pm_runtime_suspend(struct device *dev)
>         pci_dev->state_saved = false;
>         pci_dev->no_d3cold = false;
>         error = pm->runtime_suspend(dev);
> -       suspend_report_result(pm->runtime_suspend, error);
> -       if (error)
> +       if (error) {
> +               /*
> +                * -EBUSY and -EAGAIN is used to request the runtime PM core
> +                * to schedule a new suspend, so don't flag it as an error.
> +                */

KERN_DEBUG and KERN_ERR are log levels, not flags.

Besides, maybe we can use pr_err() and pr_debug() here?

> +               if (error == -EBUSY || error == -EAGAIN)
> +                       printk(KERN_DEBUG "%s(): %pF returns %d\n", __func__,
> +                              pm->runtime_suspend, error);
> +               else
> +                       printk(KERN_ERR "%s(): %pF returns %d\n", __func__,
> +                              pm->runtime_suspend, error);
> +
>                 return error;
> +       }
>         if (!pci_dev->d3cold_allowed)
>                 pci_dev->no_d3cold = true;
>
> --

Thanks,
Rafael