Hi Ricardo,
On Thu, 2 Feb 2017 20:15:16 +0100, Ricardo Ribalda Delgado wrote:
> SMBSLVCNT must be protected with the piix4_mutex_sb800 in order to avoid
> multiple buses accessing to the semaphore at the same time.
>
> Reported-by: Jean Delvare <jdelvare@xxxxxxx>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-piix4.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
> index 73cc6799cc59..c21ca7bf2efe 100644
> --- a/drivers/i2c/busses/i2c-piix4.c
> +++ b/drivers/i2c/busses/i2c-piix4.c
> @@ -592,6 +592,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
> u8 port;
> int retval;
>
> + mutex_lock(&piix4_mutex_sb800);
> +
> /* Request the SMBUS semaphore, avoid conflicts with the IMC */
> smbslvcnt = inb_p(SMBSLVCNT);
> do {
> @@ -605,10 +607,10 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
> usleep_range(1000, 2000);
> } while (--retries);
> /* SMBus is still owned by the IMC, we give up */
> - if (!retries)
> + if (!retries) {
> + mutex_unlock(&piix4_mutex_sb800);
> return -EBUSY;
> -
> - mutex_lock(&piix4_mutex_sb800);
> + }
>
> outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
> smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
> @@ -623,11 +625,11 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
>
> outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1);
>
> - mutex_unlock(&piix4_mutex_sb800);
> -
> /* Release the semaphore */
> outb_p(smbslvcnt | 0x20, SMBSLVCNT);
>
> + mutex_unlock(&piix4_mutex_sb800);
> +
> return retval;
> }
>
Thanks for the quick fix.
Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
--
Jean Delvare
SUSE L3 Support
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