On Tue, Apr 10, 2012 at 12:37:46PM +0200, Daniel Vetter wrote: > On Fri, Mar 30, 2012 at 07:46:39PM +0800, Daniel Kurtz wrote: > > The i915 is only able to generate a STOP cycle (i.e. finalize an i2c > > transaction) during a DATA or WAIT phase. In other words, the > > controller rejects a STOP requested as part of the first transaction in a > > sequence. > > > > Thus, for the first transaction we must always use a WAIT cycle, detect > > when the device has finished (and is in a WAIT phase), and then either > > start the next transaction, or, if there are no more transactions, > > generate a STOP cycle. > > > > Note: Theoretically, the last transaction of a multi-transaction sequence > > could initiate a STOP cycle. However, this slight optimization is left > > for another patch. We return -ETIMEDOUT if the hardware doesn't > > deactivate after the STOP cycle. > > > > Signed-off-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx> > > I've re-read gmbus register spec and STOP seems to be allowed even in the > first cycle. Does this patch solve an issue for you? If not, I prefer we > just drop it. Actually I'd like to keep the -ETIMEDOUT return value, so maybe we should keeep that hunk. I've picked up the previous 3 patches of this series, the once after this one here conflict (without this patch here). -Daniel -- Daniel Vetter Mail: daniel@xxxxxxxx Mobile: +41 (0)79 365 57 48 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
