Ben Dooks <ben@xxxxxxxxxxxxxxxxx> writes: > On Fri, Sep 24, 2010 at 07:37:03AM -0700, Kevin Hilman wrote: >> "Sudhakar Rajashekhara" <sudhakar.raj@xxxxxx> writes: >> >> > On Tue, Sep 21, 2010 at 09:43:28, Jon Povey wrote: >> >> When setting up to transmit, a race exists between the ISR and >> >> i2c_davinci_xfer_msg() trying to load the first byte and adjust counters. >> >> This is mostly visible for transmits > 1 byte long. >> >> >> >> The hardware starts sending immediately that MDR.STT is set. IMR trickery >> >> doesn't work because if we start sending, finish the first byte and an >> >> XRDY event occurs before we load IMR to unmask it, we never get an >> >> interrupt, and we timeout. >> >> >> >> Sudhakar Rajashekhara explains that at least OMAP-L138 requires MDR mode >> >> settings before DXR for correct behaviour, so load MDR first with >> >> STT cleared and later load again with STT set. >> >> >> >> Tested on DM355 connected to Techwell TW2836 and Wolfson WM8985 >> >> >> >> Signed-off-by: Jon Povey <jon.povey@xxxxxxxxxxxxxxx> >> >> CC: Sudhakar Rajashekhara <sudhakar.raj@xxxxxx> >> >> CC: Troy Kisky <troy.kisky@xxxxxxxxxxxxxxxxxxx> >> >> --- >> > >> > Tested-by: Sudhakar Rajashekhara <sudhakar.raj@xxxxxx> >> > >> > Tested with audio loopback on OMAP-L138, OMAP-L137 and DM365. Also tested with >> > i2cdetect function which probes all the devices on the i2c bus. >> >> >> Ben, can you queue this one for 2.6.37 with the addition of: > > If it is a worthwhile bugfix i'll send it for the next -rc. OK, yeah. It's probably better to queue for the next -rc. Thanks, Kevin -- 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
