4.20-stable review patch. If anyone has any objections, please let me know.
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From: Jarkko Nikula jarkko.nikula@linux.intel.com
commit c5eb1190074cfb14c5d9cac692f1912eecf1a5e4 upstream.
a9c8088c7988 ("i2c: i801: Don't restore config registers on runtime PM") nullified the runtime PM suspend/resume callback pointers while keeping the runtime PM enabled.
This caused the SMBus PCI device to stay in D0 with /sys/devices/.../power/runtime_status showing "error" when the runtime PM framework attempted to autosuspend the device. This is due to PCI bus runtime PM, which checks for driver runtime PM callbacks and returns -ENOSYS if they are not set.
Since i2c-i801.c doesn't need to do anything device-specific for runtime PM, Jean Delvare proposed this be fixed in the PCI core rather than adding dummy runtime PM callback functions in the PCI drivers.
Change pci_pm_runtime_suspend()/pci_pm_runtime_resume() so they allow changing the PCI device power state during runtime PM transitions even if the driver supplies no runtime PM callbacks.
This fixes the runtime PM regression on i2c-i801.c.
It is not obvious why the code previously required the runtime PM callbacks. The test has been there since the code was introduced by 6cbf82148ff2 ("PCI PM: Run-time callbacks for PCI bus type").
On the other hand, a similar change was done to generic runtime PM callbacks in 05aa55dddb9e ("PM / Runtime: Lenient generic runtime pm callbacks").
Fixes: a9c8088c7988 ("i2c: i801: Don't restore config registers on runtime PM") Reported-by: Mika Westerberg mika.westerberg@linux.intel.com Signed-off-by: Jarkko Nikula jarkko.nikula@linux.intel.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Jean Delvare jdelvare@suse.de Reviewed-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Cc: stable@vger.kernel.org # v4.18+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/pci/pci-driver.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-)
--- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -1251,30 +1251,29 @@ static int pci_pm_runtime_suspend(struct return 0; }
- if (!pm || !pm->runtime_suspend) - return -ENOSYS; - pci_dev->state_saved = false; - error = pm->runtime_suspend(dev); - if (error) { + if (pm && pm->runtime_suspend) { + error = pm->runtime_suspend(dev); /* * -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) + if (error == -EBUSY || error == -EAGAIN) { dev_dbg(dev, "can't suspend now (%pf returned %d)\n", pm->runtime_suspend, error); - else + return error; + } else if (error) { dev_err(dev, "can't suspend (%pf returned %d)\n", pm->runtime_suspend, error); - - return error; + return error; + } }
pci_fixup_device(pci_fixup_suspend, pci_dev);
- if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0 + if (pm && pm->runtime_suspend + && !pci_dev->state_saved && pci_dev->current_state != PCI_D0 && pci_dev->current_state != PCI_UNKNOWN) { WARN_ONCE(pci_dev->current_state != prev, "PCI PM: State of device not saved by %pF\n", @@ -1292,7 +1291,7 @@ static int pci_pm_runtime_suspend(struct
static int pci_pm_runtime_resume(struct device *dev) { - int rc; + int rc = 0; struct pci_dev *pci_dev = to_pci_dev(dev); const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
@@ -1306,14 +1305,12 @@ static int pci_pm_runtime_resume(struct if (!pci_dev->driver) return 0;
- if (!pm || !pm->runtime_resume) - return -ENOSYS; - pci_fixup_device(pci_fixup_resume_early, pci_dev); pci_enable_wake(pci_dev, PCI_D0, false); pci_fixup_device(pci_fixup_resume, pci_dev);
- rc = pm->runtime_resume(dev); + if (pm && pm->runtime_resume) + rc = pm->runtime_resume(dev);
pci_dev->runtime_d3cold = false;