Re: i2c: designware: prevent signals from aborting I2C transfers

From: Christian Ruppert
Date: Fri Jun 07 2013 - 04:54:38 EST


On Wed, May 22, 2013 at 10:03:11AM -0000, Mika Westerberg wrote:
> If a process receives signal while it is waiting for I2C transfer to
> complete, an error is returned to the caller and the transfer is aborted.
> This can cause the driver to fail subsequent transfers. Also according to
> commit d295a86eab2 (i2c: mv64xxx: work around signals causing I2C
> transactions to be aborted) I2C drivers aren't supposed to abort
> transactions on signals.
>
> To prevent this switch to use wait_for_completion_timeout() instead of
> wait_for_completion_interruptible_timeout() in the designware I2C driver.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Christian Ruppert <christian.ruppert@xxxxxxxxxx>
>
> ---
> drivers/i2c/busses/i2c-designware-core.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> index c41ca63..db20a28 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -580,14 +580,13 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> i2c_dw_xfer_init(dev);
>
> /* wait for tx to complete */
> - ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, HZ);
> + ret = wait_for_completion_timeout(&dev->cmd_complete, HZ);
> if (ret == 0) {
> dev_err(dev->dev, "controller timed out\n");
> i2c_dw_init(dev);
> ret = -ETIMEDOUT;
> goto done;
> - } else if (ret < 0)
> - goto done;
> + }
>
> if (dev->msg_err) {
> ret = dev->msg_err;

--
Christian Ruppert , <christian.ruppert@xxxxxxxxxx>
/|
Tel: +41/(0)22 816 19-42 //| 3, Chemin du Pré-Fleuri
_// | bilis Systems CH-1228 Plan-les-Ouates
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