[Maverick, Lucid][Pull Request][SRU] FTDI USB/Serial - ensure correct RTS/DTR behaviour

[Tim Gardner]

On 12/20/2010 07:07 PM, Hugh Blemings wrote:
>
> Buglink: http://bugs.launchpad.net/bugs/690798
> Buglink: http://bugs.launchpad.net/bugs/655868
>
> Maverick and Lucid appear to lack a reverted patch that is, I strongly
> suspect, causing issues with FTDI based USB/Serial devices, including Arduino
> boards.  Have provided further rationale in bug 690798.
>
> Mainline and Natty both have the suggested patch applied.
>
>  From original submission to LKML:
>
>
> This reverts commit 6a1a82df91fa0eb1cc76069a9efe5714d087eccd.
>
> RTS and DTR should not be modified based on CRTSCTS when calling
> set_termios.
>
> Modem control lines are raised at port open by the tty layer and should stay
> raised regardless of whether hardware flow control is enabled or not.
>
> This is in conformance with the way serial ports work today and many
> applications depend on this behaviour to be able to talk to hardware
> implementing hardware flow control (without the applications actually using
> it).
>
> Hardware which expects different behaviour on these lines can always
> use TIOCMSET/TIOCMBI[SC] after port open to change them.
>
>
> OriginalAuthor:	Johan Hovold<jhovold at gmail.com>	
> Committer:	Greg Kroah-Hartman<gregkh at suse.de>	
> Reported-by: Daniel Mack<daniel at caiaq.de>
> Reported-by: Dave Mielke<dave at mielke.cc>
> Signed-off-by: Johan Hovold<jhovold at gmail.com>
> Signed-off-by: Greg Kroah-Hartman<gregkh at suse.de>
> Signed-off-by: Hugh Blemings<hugh at canonical.com>
>   (cherry-picked from commit 677aeafe19e88c282af74564048243ccabb1c590)
>
>

This is already in the pipeline via stable 2.6.32.27 (which will be part 
of the next Maverick upload). I'll edit the commit log to add one of the 
bug numbers.

rtg
-- 
Tim Gardner tim.gardner at canonical.com