On Wed, Oct 04, 2017 at 11:43:45AM +0200, Claudio Foellmi wrote: > A very conservative check for bus activity (to prevent interference > in multimaster setups) prevented the bus recovery methods from being > triggered in the case that SDA or SCL was stuck low. > This defeats the purpose of the recovery mechanism, which was introduced > for exactly this situation (a slave device keeping SDA pulled down). > > Also added a check to make sure SDA is low before attempting recovery. > If SDA is not stuck low, recovery will not help, so we can skip it. > > Note that bus lockups can persist across reboots. The only other options > are to reset or power cycle the offending slave device, and many i2c > slaves do not even have a reset pin. > > If we see that one of the lines is low for the entire timeout duration, > we can actually be sure that there is no other master driving the bus. > It is therefore save for us to attempt a bus recovery. > > Signed-off-by: Claudio Foellmi <claudio.foellmi@xxxxxxxx> > Cc: Grygorii Strashko <grygorii.strashko@xxxxxx> > Cc: Vignesh R <vigneshr@xxxxxx> Applied with the discussed change to for-next, thanks!
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