Fix for ftdi_set_termios() glitching output
ftdi_set_termios() is constantly setting the baud rate, data bits and parity
unnecessarily on every call, . When called while characters are being
transmitted can cause the FTDI chip to corrupt the serial port bit stream
output by stalling the output half a bit during the output of a character.
Simple fix by skipping this setting if the baud rate/data bits/parity are
unchanged.
Signed-off-by: Andrew Worsley <amworsley@gmail.com>
Cc: stable <stable@vger.kernel.org>
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I had a brief run with strace on the getty and it was doing ioctl()s on
each call but it didn't look relavant to the problem. I think the issue is
that XON/XOFF flow control was being implmented via hardware - for the ixoff
to allow the user to use XON/XOFF to control output. Unfortunately it would
send 3 Control URBs updating all of the settings after each piece of input
I am trying to work around the issue of gmail messing with the tab/spacing
by submitting via SMTP via gmail which I believe should fix the issue.
The patch is against v3.2-rc2 and compiles - but no additional testing in
this kernel has been done.
Thanks
Andrew
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
b1ffb4c851