https://bugzilla.kernel.org/show_bug.cgi?id=203297 Regression, suspected but as yet unconfirmed cause: c5eb1190074c ("PCI / PM: Allow runtime PM without callback functions") backported to 4.20 stable as 39e1be324c2f. Keijo Vaara <ferdasyn@xxxxxxxxxxxxxx> reported: > After upgrading from 4.20.1 to 4.20.2 Synaptics touchpad TM-3127 on HP > 250 G5 is recognized in all logs like normal, but PCI runtime power > management seems to keep it from working shortly after module > initialization. Issuing "modprobe -r psmouse && modprobe psmouse" fixes > the issue but the device stops working again if inactive for a second or > so. This is likely caused by https://lkml.org/lkml/2019/1/11/615. > > Possible workarounds known to work: > 1) Forcing psmouse module to use imps protocol works, but disables most > of the touchpad functionality such as two finger scrolling. > 2) Disabling PCI runtime power management for the device (f.e. using tlp > RUNTIME_PM_ON_BAT=on fixes the issue) > 3) Downgrade kernel to 4.20.1 > > The bug has been reported by multiple users with different software > setups, all with HP laptops (see > https://bbs.archlinux.org/viewtopic.php?id=243677 for more info). > > The suspect commit from kernel log: > > commit 39e1be324c2f9048b013aaa190acf91b3f23b1a8 > Author: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx> > Date: Tue Oct 23 14:45:52 2018 +0300 > > PCI / PM: Allow runtime PM without callback functions > > 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@xxxxxxxxxxxxxxx> > Signed-off-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx> > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Reviewed-by: Jean Delvare <jdelvare@xxxxxxx> > Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx # v4.18+ > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
