On Thu, Mar 17, 2011 at 10:13 AM, <Bastian.Ruppert@xxxxxxxxxx> wrote: > [...] >> I wonder if there is YA hardware problem with i2c on the LogicPD >> boards. I've noticed that when I don't have the UBI board connected >> then I don't get the controller timeouts. >> > > I have some effects here, too. > We have a i2c repeater solded on our board (PCA9515AD). With this repeater > > i can reproduce the errer pretty fast. > Without this repeater solded on, the mean time before failure is much > higher. > > I can produce the error pretty fast with the ts_test tool. Without any > userland > tool using the touchscreen info or with the tool evtest, i can see the i2c > > action on the oscilloscope but it is hard to produce the error. > What does this indicate to? > Is it possible that userland can influence the kernel driver timing to > promote > the error? I don't think that userland can influence the kernel driver timing; based on my understanding of the driver [1] polling occurs from the moment the device is probe()'d. Are you modprob'ing the driver right before ts_test? Where can I see the ts_test source? >> Have you tried using the bitbanging i2c driver? I suppose that using >> the bitbanging i2c driver would be too much CPU overhead for polling >> your touchscreen... >> > > Yes, the bitbanging driver gives me "boiled NACK" errors or so sometimes, > but the system do not stall. (In my opinion, bitbanging is not the elegant > way > to do i2c). > >> Have you asked about how to implement this FDF-SCL-toggle method on >> the e2e forums? > > No, i did not. Ok. I'll post then. Best Regards, Ben Gardiner [1] http://lxr.linux.no/linux+v2.6.38/drivers/input/touchscreen/tps6507x-ts.c --- Nanometrics Inc. http://www.nanometrics.ca -- 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
