On Mon, Apr 25, 2016 at 04:33:37PM +0200, Jan Glauber wrote: > From: Peter Swain <pswain@xxxxxxxxxx> > > There is a race between the TWSI interrupt and the condition > that is required before proceeding: > > Low-level: interrupt flag bit must be set > High-level controller: valid bit must be clear > > If the interrupt comes too early and the condition is not met > the wait will time out, and the transfer is aborted leading > to very poor performance. > > To avoid this race retry for the condition ~80 µs later. > The retry is avoided on the very first invocation of > wait_event_timeout() (which tests the condition before entering > the wait and is therefore always wrong in this case). > > EEPROM reads on 100kHz i2c now measure ~5.2kB/s, about 1/2 what's > achievable, and much better than the worst-case 100 bytes/sec before. > > While at it remove the debug print from the low-level wait function. > > Signed-off-by: Peter Swain <pswain@xxxxxxxxxx> > Signed-off-by: Jan Glauber <jglauber@xxxxxxxxxx> Applied to for-next, thanks! Assigned 'true' instead of '1' to bool...
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