Thread (66 messages) 66 messages, 11 authors, 2012-02-08

patch "tty: serial: OMAP: ensure FIFO levels are set correctly in non-DMA" added to tty tree

From: paul@pwsan.com (Paul Walmsley)
Date: 2012-02-04 16:31:29
Also in: linux-omap, linux-serial

On Sat, 4 Feb 2012, Grazvydas Ignotas wrote:
It's case 1. What I wanted to say is that first char is most often
nicely dropped and does not get into the terminal, so I can just type
the command after it. But in some cases terminal gets corrupted char
instead, so I must then first get rid of it somehow to successfully
send a command, which is annoying a bit. I thought that maybe there is
code somewhere that gets rid of first bad char received and maybe it
can be tuned, but judging on further discussions it's all done by
hardware?

I've also noticed if I paste a command instead, up to 3 characters can
be lost, and in some cases I get 3 corrupted chars there instead. I
paste a command to both wake the board and read the fuel gauge just
before it updates to see how much current board was draining while
suspended. I insert 3 spaces at the start of command to be eaten by
wakeup, but if it decides to corrupt those chars instead of dropping,
the whole command is ruined. It's all at 115200 baud rate.
Aside from trying some of the muxing suggestions that Neil proposed, 
perhaps the UART driver should clear the RX FIFO if the UART detects a 
framing error?  e.g., section 17.4.4.1.3.5 "Error Detection" in the
34xx TRM vZT.


- Paul
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