[U-Boot] [PATCH] At start of autoboot check, flush any pending RX bytes

[Tom Rini]

On Mon, Jan 11, 2016 at 09:59:18AM -0700, Simon Glass wrote:
> Hi Craig,
> 
> On 20 December 2015 at 19:07, Craig McQueen
> <craig.mcqueen at innerrange.com> wrote:
> > This is to avoid the boot sequence halting due to initial "junk"
> > received on serial input.
> >
> > Signed-off-by: Craig McQueen <craig.mcqueen at innerrange.com>
> > ---
> > I have found that on the BeagleBone Black, U-Boot occasionally halts at
> > the U-Boot prompt at boot-up, whether power-up, warm external
> > reset or software reset. I have seen other people report the same issue.
> >
> > This seems to be due to U-Boot receiving "junk" data on the serial
> > console. The BeagleBone Black has a pull-down resistor which was
> > apparently added to try to mitigate this issue, but it doesn't entirely
> > fix it.
> 
> I wonder if this can be fixed for that board only?

No, and it's not -exactly- a that board only problem.  It's a HW design
issue that can show up elsewhere too.  I _think_ however in this case
the answer would be to migrate to perhaps CONFIG_AUTOBOOT_KEYED_CTRLC as
that's one of the reason various other boards use that set of options.

I would suggest bringing this up on the beaglebone list to see what the
various people that ship and support these boards think, thanks!

-- 
Tom
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