From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:46999 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751120AbbK3SHH (ORCPT ); Mon, 30 Nov 2015 13:07:07 -0500 Date: Mon, 30 Nov 2015 12:07:02 -0600 From: Bjorn Helgaas To: Imre Deak Cc: Bjorn Helgaas , "Rafael J. Wysocki" , Jani Nikula , Daniel Vetter , intel-gfx@lists.freedesktop.org, Linux PCI , Linux PM Subject: Re: [PATCH v4] PCI / PM: tune down RPM suspend error message with EBUSY and EAGAIN retval Message-ID: <20151130180702.GB29242@localhost> References: <1448648254-12639-1-git-send-email-imre.deak@intel.com> <1448699664-4178-1-git-send-email-imre.deak@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1448699664-4178-1-git-send-email-imre.deak@intel.com> Sender: linux-pci-owner@vger.kernel.org List-ID: Hi Imre, > PCI / PM: tune down RPM suspend error message with EBUSY and EAGAIN retval Please capitalize the first word, e.g., "Tune ..." Maybe "Tune down non-fatal runtime suspend error messages" would be more to the point. Or maybe "retryable," since it sounds like that's what's supposed to happen. On Sat, Nov 28, 2015 at 10:34:24AM +0200, Imre Deak 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. I looked briefly for the place in the runtime PM core where we handle EBUSY and EAGAIN specially, but I didn't find it. A pointer would be helpful. > 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) > v4: > - don't refer to log levels as flags in code comment (Rafael) > - use pr_debug(), pr_err() instead of the corresponding printk() (Rafael) The version history is very useful during development but not after merging, so I prefer it to go after the "---" marker so it doesn't get included in the permanent changelog. > Reported-by: Daniel Vetter > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92992 > CC: Bjorn Helgaas > CC: Rafael J. Wysocki > Signed-off-by: Imre Deak > --- > drivers/pci/pci-driver.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > index 4446fcb..32a9947 100644 > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -1146,9 +1146,21 @@ 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 log the event only with debug > + * log level. > + */ > + if (error == -EBUSY || error == -EAGAIN) > + pr_debug("%s(): %pF returns %d\n", __func__, > + pm->runtime_suspend, error); > + else > + pr_err("%s(): %pF returns %d\n", __func__, > + pm->runtime_suspend, error); This looks fine to me in principle. We have the device pointer, so please use dev_printk(KERN_DEBUG) and dev_err(). If you're OK with changing the semantics so the debug message is only emitted when dynamically enabled, you could use dev_dbg(). I don't know what a user is supposed to do with a message like: pci_pm_runtime_suspend(): ata_port_runtime_suspend+0x0/0x200 returns -12 It feels a little bit ... internal. Using dev_err() will help anchor it to a specific device. It's not related to a specific PC in the function, so maybe use %pf instead of %pF to get rid of the function offset and size. And the message doesn't say anything about what the return code *means*; maybe something like: ata_piix 0000:00:14.0: can't suspend now (ata_port_runtime_suspend returned -11) ata_piix 0000:00:14.0: can't suspend (ata_port_runtime_suspend returned -12) > + > return error; > + } > if (!pci_dev->d3cold_allowed) > pci_dev->no_d3cold = true; > > -- > 2.5.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html