XO battery/performance[ Devel Digest, Vol 76, Issue 21]

James Cameron quozl at laptop.org
Tue Jun 12 18:59:18 EDT 2012

On Tue, Jun 12, 2012 at 09:15:48AM -0700, Yioryos Asprobounitis wrote:
> > > > ? Perhaps your comm settings are wrong??
> > > > 115200,n,8,1 is what they 
> > > > should be set to.? 
> > > 
> > > That did the trick (thus my change in the wiki)
> > 
> > I think it was coincidence.?? Please try without it.
> At least in my setting ie XO-1.75 embedded keyboard model with the
> "problem" battery and the adapter connected to the UART 4 port and
> XO-1.75 HS keyboard running screen, n,8,1 makes all the difference.

Thanks for testing again.  Richard was using a convention that screen
does not use.  The reason I thought it was coincidence was that the
screen program does not behave any differently for me with or without
,n,8,1 and the source code of screen confirms there should be no


This is the function that processes the baud rate option.  It is the
only place in the code where serial port configuration is set.  There
is nothing in there that should notice the presence or absence of

That it works differently for you, reproducibly, means there is some
other effect happening, and we should try to get to the bottom of it.
Unexplained effects can lead to problems later on.

Could you please do another test, to verify that screen is not
configuring the serial port any differently with or without ,n,8,1.
You don't need to connect the two laptops together, just use the one
you use as the serial terminal.  The test uses the stty program to
display the serial port configuration.

1.  start "screen /dev/ttyUSB0 115200",

2.  exit screen with ctrl+a k,

3.  show the serial port configuration with "stty --all < /dev/ttyUSB0",

4.  start "screen /dev/ttyUSB0 115200,n,8,1",

5.  exit screen with ctrl+a k,

6.  show the serial port configuration with "stty --all < /dev/ttyUSB0",

7.  start "screen /dev/ttyUSB0 9600,n,8,1",

8.  exit screen with ctrl+a k,

9.  show the serial port configuration with "stty --all < /dev/ttyUSB0".

When I do this test with an XO-1.75 os13, there is never any
difference in the number of bits per character setting, which is shown
by stty as cs7 vs cs8, or in the number of stop bits, which is shown
as -cstopb (for one), and cstopb (for two).  I do see the baud rate
difference when I have changed the baud rate.

James Cameron

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