Re: [PATCH 02/10] i2c: i801: Improve disabling runtime pm

[Jean Delvare <jdelvare@suse.de>]

On Sun, 01 Aug 2021 16:17:48 +0200, Heiner Kallweit wrote:
> Setting the autosuspend delay to a negative value disables runtime pm in
> a little bit smarter way, because we need no cleanup when removing the
> driver. Note that this is safe when reloading the driver, because the
> call to pm_runtime_set_autosuspend_delay() in probe() will reverse the
> effect. See update_autosuspend() for details.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
>  drivers/i2c/busses/i2c-i801.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index 362e74761..bdb619bc0 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -1628,7 +1628,7 @@ 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_get_sync(&pdev->dev);
> +		pm_runtime_set_autosuspend_delay(&pdev->dev, -1);

Surprisingly, very few drivers use this. But this indeed looks correct.

>  	}
>  
>  	if ((function & ACPI_IO_MASK) == ACPI_READ)
> @@ -1668,11 +1668,6 @@ static void i801_acpi_remove(struct i801_priv *priv)
>  
>  	acpi_remove_address_space_handler(adev->handle,
>  		ACPI_ADR_SPACE_SYSTEM_IO, i801_acpi_io_handler);
> -
> -	mutex_lock(&priv->acpi_lock);
> -	if (priv->acpi_reserved)
> -		pm_runtime_put(&priv->pci_dev->dev);
> -	mutex_unlock(&priv->acpi_lock);
>  }
>  #else
>  static inline int i801_acpi_probe(struct i801_priv *priv) { return 0; }

Reviewed-by: Jean Delvare <jdelvare@suse.de>

-- 
Jean Delvare
SUSE L3 Support