On Mon, 9 Feb 2009 16:02:55 +0100, Rodolfo Giometti wrote: > On Mon, Feb 09, 2009 at 02:55:46PM +0000, Ben Dooks wrote: > > On Fri, Feb 06, 2009 at 04:23:17PM +0100, Rodolfo Giometti wrote: > > > It could happen that an i2c adapter may lock the bus due due > > > electrical problems, so the user may recover this stale state by using: > > > > > > $ echo 1 > /sys/class/i2c-adapter/i2c-0/reset > > > > > > Signed-off-by: Rodolfo Giometti <giometti@xxxxxxxx> > > > > There doesn't seem to be any locking to stop issuing a reset during > > an extant transaction... should the controller driver deal with > > cancelling any outstanding transactions? > > I think this should be done inside each adapter driver since it's > an adapter specific issue. > > If you see next patch of this patchset you can see that the adapter > i2c-pxa aborts any transfer currently under way during reset. I disagree. An i2c bus driver should never get stuck in the middle of a transaction (that is, with i2c_adapter->bus_lock held.) If a transaction fails, the driver should timeout and return. Thus I think Ben is right and it would make a lot of sense to have function write_adapter_reset take i2c_adapter->bus_lock. This guarantees that all bus drivers will get locking right and won't allow resetting in the middle of a (non-stuck) transaction. -- Jean Delvare -- 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
