Hi Grygorii, On Mon, Nov 24, 2014 at 03:26:10PM +0200, Grygorii Strashko wrote: > On 11/23/2014 10:36 PM, Uwe Kleine-König wrote: > > On Fri, Nov 21, 2014 at 09:33:22PM +0200, Grygorii Strashko wrote: > >> On 11/21/2014 09:07 PM, Uwe Kleine-König wrote: > >>> On Thu, Nov 20, 2014 at 12:03:07PM +0200, Grygorii Strashko wrote: > >>> Just another general comment about the driver that doesn't influence the > >>> correctness of this patch: The i2c-davinci driver is quite quick to > >>> reset the bus. I wonder how often this reset triggers. Is the bus in > >>> question less "stable" than others? > >> > >> In comparison to ..? :) > > In comparison to other bus drivers in other SoCs. I know this might be > > hard to answer. I just wonder where the reason for this has to be > > located. Strange hardware? Software bug? Or is this SoC just operating > > with strange slaves more often than others? > > Davinci driver does reset in two cases: > - when I2C transaction isn't completed due to timeout (no irq received) > - when BB is detected > both cases are reasonable, because in 1st case HW state is undefined > in 2d case - Davinci I2C supports only master mode and if BB detected > we need perform some recovery procedure. note that for multi-master scenarios bus recovery might be bad. So that has not necessarily something to do with "master mode only". > Also, this patch doesn't introduce functional changes - it's just code > reworking intended to reuse I2C bus recovery infrastructure Yeah this is fine, and my concern shouldn't stop your patch from getting in as it is an improvement for sure. Still I only had to handle BB once in my linux lifetime, and that was for a different reason. (Machine doing massive i2c transfers and so a client was often holding the bus busy when the watchdog resetted the cpu.) So I just wondered how often the need for recovery arises. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- 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
