On 3. okt. 2015 00.29.26 CEST, Robert Nelson <[email protected]> wrote: >On Fri, Oct 2, 2015 at 5:23 PM, Brian Adams <[email protected]> wrote: >we are still experiencing a 4.5% boot failure rate >For a board that "stops" what happens when you plug in a usb-usart, >are you really in u-boot? >(u-boot prompt should echo back on the first enter)
Characters on uart0 was clearly, without any doubt, what interrupted the boot when I did my testing last winter (that was the unmodified uboot); http://www.mikini.dk/index.php/category/beaglebone-black/boot-issue I checked numerous times with a serial connection that uboot was indeed waiting for commands on uart0 in this condition. As for the cause, I still have a suspicion towards the circuitry design around the buffer U15 and its OE and _OE (discussed in http://www.mikini.dk/index.php/2014/10/beaglebone-black-periodic-boot-failure-establishing-failure-rate-and-possible-cause). But I guess nobody wants to waste time analyzing this issue on a stale design such as the BB. >One reason i can't lock down u-boot by default, CircuitCo's tester >expect to take over u-boot to program the eeprom as part of their >tester machines.. And that is indeed a valid argument for keeping the feature. Changing stuff in factory is non-trivial. But still you would probably be able to identify the one character that their testers actually do use to stop boot and only react to that one. That would lower possibility by 2^8 (if all chars are still valid in current uboot). Or future CircuitCo production image uboots could be built from a branch/fork/patchset that stops on one char as now. This would allow the proper "wait for string" solution to be implemented in the default uboot. People doing their own builds like Brian would then actually build a uboot that doesn't intendedly ruin boot stability. It is really disheartening to know that people are still fighting this problem even though a solution is well-known and has been for such a long time. Mikkel -- Sendt fra min Android telefon med K-9 Mail. Undskyld hvis jeg er lidt kortfattet. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
