From 834aa6f30c2f5f5ab7c858e37800c1a19dfde2fb Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Thu, 15 Mar 2012 18:11:05 +0100 Subject: [PATCH 1/2] i2c-core: Comment says "transmitted" but means "received" Fix that. Also convert this and the related comment to proper commenting style. Signed-off-by: Wolfram Sang Signed-off-by: Jean Delvare --- drivers/i2c/i2c-core.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 1e5606185b4f..e9c18939eda7 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1386,8 +1386,10 @@ int i2c_master_send(const struct i2c_client *client, const char *buf, int count) ret = i2c_transfer(adap, &msg, 1); - /* If everything went ok (i.e. 1 msg transmitted), return #bytes - transmitted, else error code. */ + /* + * If everything went ok (i.e. 1 msg transmitted), return #bytes + * transmitted, else error code. + */ return (ret == 1) ? count : ret; } EXPORT_SYMBOL(i2c_master_send); @@ -1414,8 +1416,10 @@ int i2c_master_recv(const struct i2c_client *client, char *buf, int count) ret = i2c_transfer(adap, &msg, 1); - /* If everything went ok (i.e. 1 msg transmitted), return #bytes - transmitted, else error code. */ + /* + * If everything went ok (i.e. 1 msg received), return #bytes received, + * else error code. + */ return (ret == 1) ? count : ret; } EXPORT_SYMBOL(i2c_master_recv); From 8ee161ce5e0cfc689eb677f227a6248191165fac Mon Sep 17 00:00:00 2001 From: Ville Syrjala Date: Thu, 15 Mar 2012 18:11:05 +0100 Subject: [PATCH 2/2] i2c-algo-bit: Fix spurious SCL timeouts under heavy load When the system is under heavy load, there can be a significant delay between the getscl() and time_after() calls inside sclhi(). That delay may cause the time_after() check to trigger after SCL has gone high, causing sclhi() to return -ETIMEDOUT. To fix the problem, double check that SCL is still low after the timeout has been reached, before deciding to return -ETIMEDOUT. Signed-off-by: Ville Syrjala Cc: stable@vger.kernel.org Signed-off-by: Jean Delvare --- drivers/i2c/algos/i2c-algo-bit.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index 525c7345fa0b..24f94f4ae395 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -103,8 +103,14 @@ static int sclhi(struct i2c_algo_bit_data *adap) * chips may hold it low ("clock stretching") while they * are processing data internally. */ - if (time_after(jiffies, start + adap->timeout)) + if (time_after(jiffies, start + adap->timeout)) { + /* Test one last time, as we may have been preempted + * between last check and timeout test. + */ + if (getscl(adap)) + break; return -ETIMEDOUT; + } cond_resched(); } #ifdef DEBUG