Bug 165457 - Can't deactivate "Enable flow control" setting
Summary: Can't deactivate "Enable flow control" setting
Alias: None
Product: konsole
Classification: Applications
Component: general (show other bugs)
Version: unspecified
Platform: Ubuntu Linux
: NOR normal
Target Milestone: ---
Assignee: Konsole Developer
Depends on:
Reported: 2008-07-01 02:02 UTC by ken manheimer
Modified: 2009-06-21 11:22 UTC (History)
14 users (show)

See Also:
Latest Commit:
Version Fixed In:


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Description ken manheimer 2008-07-01 02:02:37 UTC
Version:           2.1 (using KDE 4.0.83)
Installed from:    Ubuntu Packages
OS:                Linux

in konsole's Advanced tab of Edit current profile, the checkbox "Enable flow control using Ctrl+S , Ctrl+Q" is set and grayed out, so that the user cannot configure konsole to disable flow control.  this is a problem for applications that handle the handshaking themselves, and use flow control keys - ctl-s - for other things: emacs, nano, etc.

a workaround is to use 'stty -ixon' to disable flow control in the terminal.  that must be done locally, before any remote logins, and it sucks to have to remember to do so.  some won't figure it out.

this was a known problem in kde 4.1 beta 1, according to 
(search for "Enable flow control".)
Comment 1 Robert Knight 2008-07-01 04:39:33 UTC
The problem you mention with Emacs/Nano etc. is fixed in the current version of Konsole without needing that option to be unchecked.

When emacs/nano etc. changes the terminal flow control settings Konsole now notices and avoids showing the warning accordingly.
Comment 2 ken manheimer 2008-07-01 05:12:05 UTC
As far as i can tell, it's still broken for remote tty emacs (nano, etc) sessions.  This is a big problem for me, and probably for others.

Out of curiosity, why is the option disabled?  Is it broken?
Comment 3 ken manheimer 2008-07-01 05:16:15 UTC
i take it back - sometimes changes in the flow characteristics of the remote sessions are conveyed back to be noticed by konsole.  sometimes, however, they are not - i noticed this problem in one of those situations.  i'll see if i can reproduce it, and report it here.
Comment 4 Florian Loitsch 2008-09-29 12:22:50 UTC
Not being able to turn off flow control also breaks searching in the history of bash/zsh. ctrl-r starts a back-search, but I frequently use ctrl-s to come back to a found item I accidentally skipped.
ex: ctrl-r ls  [to search for the last line using ls]
    ctrl-r ctrl-r  [search the next matches]
    [I find that I skipped the entry I actually wanted to find]
    ctrl-s ctrl-s  [to come back to the skipped match]
Comment 5 ken manheimer 2008-11-13 21:23:51 UTC
(In reply to comment #1)
> The problem you mention with Emacs/Nano etc. is fixed in the current version of
> Konsole without needing that option to be unchecked.
> When emacs/nano etc. changes the terminal flow control settings Konsole now
> notices and avoids showing the warning accordingly.

this has continued to be a problem, previously sporadic and now, after my upgrade to kde 4.10, constant.  every new konsole windows starts catching flow control characters, preventing use of ctrl-s in bash and tty emacs, and even worse, ctrl-x ctrl-s (save file) in tty emacs.  the option to disable flow control handling is still inhibited, leaving it permanently on.

my workaround is to issue 'stty -ixon' to my shell, when i start a new window.  i am reluctant to make that a part of my permanent shell initialization, since i use it on other platforms where this is not broken (and i don't know the collateral consequences of disabling flow control everywhere).

i continue to wonder why the option is not just re-enabled, so the configuration can be brought directly to bear where it is a problem?
Comment 6 MartinG 2008-11-21 10:38:44 UTC
I too use ctrl-r *and* ctrl-s a lot in my everyday Bash tasks. Would love to be able to turn off that flow control catching in konsole. I also wonder why it is grayed out.
(Fedora Rawhide, kdelibs-4.1.2-5.fc10.i386)
Comment 7 Sendil 2008-12-11 21:27:22 UTC
I found a workaround, just go to the configure shortcuts, and assign the Cntrl+S shortkey to some other commands :).  ( I used to clear Scrollback, or one may use as alternate copy shortcut). 
Comment 8 Sérgio Basto 2008-12-30 18:58:24 UTC
put : 
stty -ixon

on $HOME/.bashrc workaround this problem. 
Comment 9 Paul Pogonyshev 2009-01-10 11:23:58 UTC
I didn't see an answer to this question: "Out of curiosity, why is the option disabled? Is it broken?".

What is the point of not fixing it?  Judging by the number of votes this annoys _a lot_ of people.  Why not just simply enable that preference setting and be done with it?
Comment 10 Milos Jakubicek 2009-02-16 20:35:59 UTC
I've same question as Paul -- why is that checkbox disabled at all?
Comment 11 Kurt Hindenburg 2009-03-06 05:37:00 UTC
Robert, I see a comment in the code saying that there is a bug in kde 4.1 which prevents flow control from working.  I couldn't find anything mentioning what the bug was.
Comment 12 jarauh 2009-03-24 19:55:43 UTC
Well - apparently flow control works too well for many people.

I do like the possibility to have flow control, but it would be better to make the shortcut key customizable, given that Ctrl-S is defined by bash.
Comment 13 Kurt Hindenburg 2009-04-17 16:36:49 UTC
SVN commit 955413 by hindenburg:

Allow flow control to be disabled.  The current session will not be affected.

BUG: 165457

 M  +0 -5      EditProfileDialog.cpp  

WebSVN link: http://websvn.kde.org/?view=rev&revision=955413
Comment 14 Sérgio Basto 2009-05-31 23:14:44 UTC
I seeing this patch still is not applied on kde-4.2.3 ! 

cat kdebase-4.2.3/apps/konsole/src/EditProfileDialog.cpp
Comment 15 Kevin Kofler 2009-05-31 23:24:28 UTC
Nor 4.2.4 for that matter.
Comment 16 Kevin Kofler 2009-05-31 23:25:21 UTC
(FWIW, I think it's too late for 4.2.4 now and this means backporting this is probably moot now. Still, why wasn't the fix backported back when it was made?)
Comment 17 Frederik Schwarzer 2009-05-31 23:45:58 UTC
As mentioned, the option was disabled due to a bug in KDE. Maybe noone stepped forward to test if that bug still is there in 4.2.
Now it is too late. 4.2.4 is tagged, there will likely be no 4.2.5 and 4.3 is close.
Please let this issue go for 4.2.x and test if it works like it should in 4.3 beta x instead. For me it does. :)
Comment 18 Kevin Kofler 2009-05-31 23:54:39 UTC
We've shipped 4.2.2 builds with that patch in Fedora and it worked just fine. (The patch accidentally got dropped in our 4.2.3 builds because we thought it's fixed upstream, which is part of why I'm complaining about the fix not having been backported.)
Comment 19 Frederik Schwarzer 2009-06-01 00:23:45 UTC
I am not a Konsole developer, so this is just my personal opinion.

I understand your resentment. That's nothing that can be undone now though.
It would have been nice to see that fix backported, no question, but it is your fault dropping the patch.

Robert, who did most of the KDE 4 work in Konsole seems a bit busy with other stuff these days. That's unfortunate but cannot be avoided either. There are some projects inside KDE that are barely maintained.

If it was a few weeks earlier, I would backport and test it but it is not and I was not aware of this not-backported-yet situation until today. Again, unfortunate but also just happened.

Comment 20 Kevin Kofler 2009-06-05 02:27:45 UTC
SVN commit 977678 by kkofler:

Allow flow control to be disabled.  The current session will not be affected.

CCBUG: 165457

(backport revision 955413 by hindenburg as this works just fine since at least 4.2.2, probably since 4.2.0)

 M  +0 -5      EditProfileDialog.cpp  

WebSVN link: http://websvn.kde.org/?view=rev&revision=977678
Comment 21 Kevin Kofler 2009-06-05 02:28:44 UTC
(The backport may never end up in a release, but at least people building the 4.2 branch will pick it up.)