[U-Boot] [PATCH v2] NS16550: buffer reads

[Wolfgang Denk]

Dear Simon Glass,

In message <CAPnjgZ34FFotBBiqb=Y5xsuyRiavOWud5G2sy9GModsG4LB6=w at mail.gmail.com> you wrote:
> 
> > A general question: is the issue with input as such, or with echoing this
> > input?
> 
> The problem is in echoing the input, since this requires the uart to
> wait once its transmit FIFO is full. While it is waiting (and not
> checking the receive side), it misses characters coming from the other
> end. Basically we need to constantly check the receiving side while we
> are transmitting.

No, we do not.

U-Boot is strictly single tasking. This is one of the fundamental
design principles. We do not receive network packets while sending
ourself, or when doing other things. We do not receive characters on
the serial line while sending characters, or when doing other things.

This is known behaviour, and you should just adapt to it. I don't know
what exactly is your situation when you run into such problems - the
recommended approach for example when remote-controlling U-Boot is to
wait for the next input prompt before sending the next line of
characters - and stop after the newline, until you receive the next
prompt.

Best regards,

Wolfgang Denk

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