3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ville Syrjala <syrj...@sci.fi>
commit 8ee161ce5e0cfc689eb677f227a6248191165fac upstream.
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 <syrj...@sci.fi>
Signed-off-by: Jean Delvare <kh...@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/i2c/algos/i2c-algo-bit.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- 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_dat
* 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
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