[PATCH RESEND] i2c: i801: Stop using pm_runtime_set_autosuspend_delay(-1)

Heiner Kallweit
2021-09-07T20:33:52Z

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@BYAPR11MB3256.namprd11.prod.outlook.com/T/#t

Fixes: 4e60d5dd10cd ("i2c: i801: Improve disabling runtime pm")
Reported-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
- 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