On Tue, Sep 7, 2021 at 10:33 PM Heiner Kallweit <hkallweit1@xxxxxxxxx> wrote: > > The original change works as intended, but Andy pointed in [0] that now > userspace could re-enable RPM via sysfs, even though we explicitly want > to disable it. So effectively revert the original patch, just with small > improvements: > - Calls to pm_runtime_allow()/pm_runtime_forbid() don't have to be > balanced, so we can remove the call to pm_runtime_forbid() in > i801_remove(). > - priv->acpi_reserved is accessed after i801_acpi_remove(), and according > to Robert [1] the custom handler can't run any longer. Therefore we > don't have to take priv->acpi_lock. > > [0] https://www.spinics.net/lists/linux-i2c/msg52730.html > [1] https://lore.kernel.org/linux-acpi/BYAPR11MB32561D19A0FD9AB93E2B1E5287D39@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#t > > Fixes: 4e60d5dd10cd ("i2c: i801: Improve disabling runtime pm") > Reported-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> > Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael@xxxxxxxxxx> > --- > - Resend because I missed to cc linux-i2c list > --- > drivers/i2c/busses/i2c-i801.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c > index 1f929e6c3..f3c79942c 100644 > --- a/drivers/i2c/busses/i2c-i801.c > +++ b/drivers/i2c/busses/i2c-i801.c > @@ -1623,7 +1623,7 @@ i801_acpi_io_handler(u32 function, acpi_physical_address address, u32 bits, > * BIOS is accessing the host controller so prevent it from > * suspending automatically from now on. > */ > - pm_runtime_set_autosuspend_delay(&pdev->dev, -1); > + pm_runtime_get_sync(&pdev->dev); > } > > if ((function & ACPI_IO_MASK) == ACPI_READ) > @@ -1890,9 +1890,6 @@ static void i801_remove(struct pci_dev *dev) > { > struct i801_priv *priv = pci_get_drvdata(dev); > > - pm_runtime_forbid(&dev->dev); > - pm_runtime_get_noresume(&dev->dev); > - > i801_disable_host_notify(priv); > i801_del_mux(priv); > i2c_del_adapter(&priv->adapter); > @@ -1901,6 +1898,10 @@ static void i801_remove(struct pci_dev *dev) > > platform_device_unregister(priv->tco_pdev); > > + /* if acpi_reserved is set then usage_count is incremented already */ > + if (!priv->acpi_reserved) > + pm_runtime_get_noresume(&dev->dev); > + > /* > * do not call pci_disable_device(dev) since it can cause hard hangs on > * some systems during power-off (eg. Fujitsu-Siemens Lifebook E8010) > -- > 2.33.0 >
