On Sat, Nov 22, 2014 at 11:47 AM, Alexander Kochetkov <al.kochet@xxxxxxxxx> wrote: > In a multimaster environment, after IP software reset, BB-bit value doesn't > correspond to the current bus state. It may happen what BB-bit will be 0, > while the bus is busy due to another I2C master activity. > > Any transfer started when BB=0 and bus is busy wouldn't be completed by IP > and results in controller timeout. More over, in some cases IP could > interrupt another master's transfer and corrupt data on wire. > > The commit implement method allowing to prevent IP from entering into > "controller timeout" state and from "data corruption" state. > > The one drawback is the need to wait for 10ms before the first transfer. > > Tested on Beagleboard XM C. > Tested on BBB and AM437x Starter Kit by Felipe Balbi. > > Signed-off-by: Alexander Kochetkov <al.kochet@xxxxxxxxx> > Tested-by: Felipe Balbi <balbi@xxxxxx> > Reviewed-by: Felipe Balbi <balbi@xxxxxx> This patch recently hit linux-next (as commit 903c3859f77f) and boot breakage[1] in next-20141124 on OMAP3530 Beagle and Overo/Tobi boards was bisected down to this commit. Kevin [1] http://status.armcloud.us/boot/?next-20141124&omap -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
