Scrolling issues in edit command

[Guillermo Rodriguez Garcia]

Hello,

2016-04-05 10:14 GMT+02:00 Uwe Kleine-König <u.kleine-koenig at pengutronix.de>:
> On Tue, Apr 05, 2016 at 09:52:39AM +0200, Guillermo Rodriguez Garcia wrote:
>> 2016-04-04 22:07 GMT+02:00 Uwe Kleine-König <u.kleine-koenig at pengutronix.de>:
>> > Hello,
>> >
>> > On Wed, Mar 30, 2016 at 05:38:53PM +0200, Guillermo Rodriguez Garcia wrote:
>> >> I am trying to setup Barebox on a SAMA5D3-Xplained board. I started
>> >> with barebox-2016.03.0. So far things are looking good.
>> >>
>> >> I have found that I have problems in the 'edit' command, when trying
>> >> to scroll using the arrow keys. Scrolling up inserts random "A"
>> >> characters in the text, scrolling down inserts random "B" characters.
>> >> I am using minicom as the terminal. I don't remember seeing this
>> >> before with older versions of barebox on different boards.
>> >
>> > Can you instrument your serial driver to count/notice overflow events?
>>
>> You mean in barebox, or in the host where I'm running minicom/microcom?
>
> in barebox.

I can inspect the UART's status register using md and clear the
overrun bit using mw.

Yes, both the scrolling problem and the "missing chars problem" when
pasting text in barebox are associated with overruns.

Still I don't understand why pasting the same text in the command line
does not result in an overrun.

Perhaps "edit" is so busy repainting the screen that the incoming
characters are not handled in time?

> Also, what is your rs232 hardware? Some usb-to-rs232
> adapters are not reliable. The native 8250 ports on PCs are good ones I
> think.

It is a USB to rs232 converter but I am also using this on other
boards running barebox (older version of barebox though, and different
target hardware) and no problems there.

Just to be safe I repeated the tests on a PC that has native serial
ports. That one is a Windows box so I used PuTTY. On that setup I do
not see the "missing chars problem" , however the scrolling problem
still exists (random "A" and "B" characters inserted while scrolling).

I am wondering: If I am correct, serial in/out in barebox is not
interrupt-driven. Plus, the default UART in the sama5d3_xplained board
that I am using (DBGU) has no FIFOs. Plus, "edit" does a lot of
repaint work while editing. Could it be the case that received chars
are being missed by barebox due to the repainting work in "edit" ?

Best,

Guillermo Rodriguez Garcia
guille.rodriguez at gmail.com