Cures for 6.4.4 Video Crashes & Snags, Final Edition

[utu]

Here is the toolkit of work-arounds I have found and use.
I invite your comments and additions to the same. The last
paragraph indicates a satisfactory 'final' state for me.

1...If the video problem still leaves you some modicum of control,
for example if your problem is missing frames on windows,
or if the only problem is that windows can't remember
to come up un-maximized, and BEFORE going to step two,
try the following:
a. unplug & replug mouse's nano; and/or
b. LXDE Menu item Preferences/(Re-) start ... Compiz; and/or
c. LXDE Menu item Preferences/Compiz...Mgr/Category Utility/,
for any fixes appropriate to your hardware.

2...If step one didn't solve your problem, or If your problem
is more serious as in an unresponsive keyboard, and/or
a cpu has gone into overload, then first try 2a, then 2b...
a. if lxpanel is set to hide-when-not-in-use, cancel GUI choice
immediately prior to hwniu, per LXDE bug report. If 2a fails,
b. ctrl-alt-backspace to reset X and re-gain control; likely not
100% successful, and work in progress may-be, and if using
Network Manager, wi-fi connection will-be lost.
If this doesn't work, then
c. reboot; likely 100% successful, but same hazards as in 2b.

3...For a more permanent fix, consider giving up on some complexity:
a. add no3d to /mnt-system/boot/syslog/syslog.cfg to disable Compiz.
b. uncheck the lxpanel hiding option.

After using Knoppix 6.4.4 for a while with no3d, I find about the
only video problem that occasionally turns up is with the lxpanel set
with the hide-when-not-in-use option. Now, usually solved with 2a.
I've not needed 2b since making the 2a modification in the GUI.
A big PLUS in the no3d case is an enormous improvement in apparent
responsiveness of the system to keyboard and/or GUI commands.

[krishna.murphy]

Here is the toolkit of work-arounds I have found and use.
I invite your comments and additions to the same. The last
paragraph indicates a satisfactory 'final' state for me.

1...If the video problem still leaves you some modicum of control,
for example if your problem is missing frames on windows,
or if the only problem is that windows can't remember
to come up un-maximized, and BEFORE going to step two,
try the following:
a. unplug & replug mouse's nano; and/orWhat is a "mouse's nano"? Are you talking about a wireless mouse USB transceiver, perhaps?

b. LXDE Menu item Preferences/(Re-) start ... Compiz; and/or
c. LXDE Menu item Preferences/Compiz...Mgr/Category Utility/,
for any fixes appropriate to your hardware.

2...If step one didn't solve your problem, or If your problem
is more serious as in an unresponsive keyboard, and/or
a cpu has gone into overload, then first try 2a, then 2b...
a. if lxpanel is set to hide-when-not-in-use, cancel GUI choice
immediately prior to hwniu, per LXDE bug report. If 2a fails,Huh? "hwinu"=???

b. ctrl-alt-backspace to reset X and re-gain control; likely notI've never gotten hotkey-combo this to work, nor the ctrl-Alt-Fx windows to go that way (need chvt x)

100% successful, and work in progress may-be, and if using
Network Manager, wi-fi connection will-be lost.
If this doesn't work, then
c. reboot; likely 100% successful, but same hazards as in 2b.

3...For a more permanent fix, consider giving up on some complexity:
a. add no3d to /mnt-system/boot/syslog/syslog.cfg to disable Compiz.
I suspect you mean /mnt-system/boot/syslinux/syslinux.cfg - that's what it is in 6.2, anyway

b. uncheck the lxpanel hiding option. Where?


After using Knoppix 6.4.4 for a while with no3d, I find about the
only video problem that occasionally turns up is with the lxpanel set
with the hide-when-not-in-use option. Now, usually solved with 2a.
I've not needed 2b since making the 2a modification in the GUI.
A big PLUS in the no3d case is an enormous improvement in apparent
responsiveness of the system to keyboard and/or GUI commands.

Thanks for pulling this together, and

Cheers!
Krishna :mrgreen:

[Forester]

What is a "mouse's nano"?


The mouse you use in the nano editor. :)

[utu]

Just like Washington DC, nothing's ever 'final' here.

@ Krishna

Hi, Krishna.
Thanks for getting us un-polluted from the rainman.

I should have given a little more background, I suppose.
My video is i915. I use a 'nano' wireless mouse. 'nano' is the
transceiver that sits in USB slot 4 on my laptop.

'hwinu' look at the line just above it.
If you've found the lxpanel GUI to set hide-when-not-in-use,
under the Panel Settings/Advanced tab of the GUI,
after you check that box, uncheck the box just above it.
I call that box 'rsancbmw', but I thought that might be too
vague.

Touche. I mis-wrote syslog when I meant syslinux. in 3a.

I suspect ctl-alt-backspace may depend on hardware. For my
laptop it works on almost any distro. I know there is a
way to disable it, but I don't remember what that is.

@ Forester

FYI I believe that 'Occam's Razor' may be interpreted to mean:
"It's better not to know too much about some things".

[utu]

For completeness, here's the LXDE bug report that suggests the obscure refinement 2a:

http://sourceforge.net/tracker/?func=detail&aid=3030510&group_id=180858&atid=894869

Note how unimportant it was assumed to be, and how it's 'fixed' already. As If.

[FlameWeasel]

3...For a more permanent fix, consider giving up on some complexity: a. add no3d to /mnt-system/boot/syslog/syslog.cfg to disable Compiz. b. uncheck the lxpanel hiding option. Thanks, perfect timing on posting that. I just now decided to search for how to disable Compiz, since I find it incredibly annoying. :) Is it possible to add this option somewhere in the boot defaults so that I don't have to enter it manually? I vaguely remember, back around Knoppix 3.7, that I could just edit the ISO (obviously before burning it) with a hex editor to change some of the boot defaults. One of the non-compressed boot files had the default options in it somewhere, with a huge block of "##############" (commented shell script) that could be overtyped or deleted to provide padding for people who wanted to change them, without having to go through the full remastering process.

[utu]

@ FlameWeasel

Welcome to the forum, FlameWeasel.

I am embarassed to admit you have uncovered my typos in the above line.
It should read /mnt-system/boot/syslinux/syslinux.cfg. (syslinux not syslog)

This is how I disable Compiz in my liveUSB set-up. Just re-defines the DEFAULT declarations.
No re-mastering here. Just another advantage to the LiveUSB approach.

The equivalent in a LiveCD, without remastering, is just to use a
cheatcode at the start: just add 'knoppix no3d' at the start of the boot process,
without the quotes, of course.

I don't hate Compiz, I just don't have a use for it.
The improvement in responsiveness without it is something I can appreciate.

If you have some other arrangement than Knoppix 6.2 or 6.4 and LiveCD or LiveUSB,
we may have to call in our gurus. My scope is pretty small.

[FlameWeasel]

@ FlameWeasel Welcome to the forum, FlameWeasel. Welcome yourself! I've been around longer than you! :) :) (Actually, this is my second account here; the first was set up using a Yahoo email address, and I forgot the passwords to both so was locked out of it.)
I am embarassed to admit you have uncovered my typos in the above line.
It should read /mnt-system/boot/syslinux/syslinux.cfg. (syslinux not syslog)
I think that was Krishna Murphy; my Linux configuration knowledge is almost nonexistent. Programming, no problem; configuring, no way. :( Many thanks, though. Just tried it, and it's blazingly fast compared to with Compiz running. (I think the flaming closing windows are cute, but I'd rather have a fast system without memory leaks and occasional crashes.)

[utu]

Considering your number of posts,
I thought maybe you thought you weren't welcome.

[FlameWeasel]

Considering your number of posts,
I thought maybe you thought you weren't welcome.
Well, I thought I'd try replying through a "notification", but the board says you cannot receive them, so I guess I'll write publicly.

I appreciate the thought. It's not exactly that, though, but close. I've used the Knoppix forum on and off for far longer than this account has existed; I don't remember what my previous accounts were here, but I started using Knoppix, and participating here, in early 2004. (Shortly thereafter, I built a new computer and had to switch to Morphix, because Klaus refused to put the "unfree" NVidia video drivers into Knoppix, but still visited here occasionally, and then I moved to a place without internet for a while, and then moved back to civilization, and so on and so forth. You get the idea. Anyway.)

There are two reasons I don't hang around here much. First, because I really have very little to contribute. My technical knowledge of Linux is not high, and the questions here are mostly about Knoppix or Linux configuration. If someone wanted to know about C++ programming or scripting, which were my areas, they probably wouldn't be asking here.

The second reason is, because I almost never get an answer here. Perhaps the forum is simply too dead. Usually, either no one responds, or I get some smart-ass nonsense about "you must prove to us that your computer is flawless, your optical disk was burned perfectly, and that you have recently brushed your teeth before we will condescend to think about the problem that you claim to have experienced but that we do not believe really exists." Why bother, no one is going to answer anyway.

Tonight I fixed a problem that I have asked about, and I believe seen asked, repeatedly. Knoppix has a tendency to blow up the X11 server due to memory leaks. This was why I hated Compiz -- it's so leaky that it causes crashes frequently. When that happens, Knoppix simply kills all the processes and shuts down, with no possibility of recovering data that is on the ramdisk.

It's a stupid design, and if I were dictator, Klaus would be shot for it. Well, ok, maybe thrown into the scorpion pit instead. "Dipl.Ing." my hairy ass, this would be unacceptable from a first-year programming student.

I had managed to track down where the X11 server was started from, and I changed the script so that it was in a forever loop. That usually works -- the X11 server dies horribly, then my loop restarts it. About 80% of the time, I could now save my data.

But sometimes the crash is because cached code pages got corrupted somehow, and when that happens, the X11 server crashes again as soon as it restarts -- an infinite loop of crashes. Other times, I'm not sure what happens, but the machine simply freezes up; it seems like the machine has gone down to a text console in the background, but graphics mode is still set, and nothing works to view the text console. Maybe the keyboard is still in raw mode, or something. I don't know. Nothing that I've tried has worked, not even the so-called "magic sysreq" -- at best, that will sometimes cause the machine to shut down the rest of the way, which is incredibly irritating. I don't want to shut it down, I want to save my unsaved data.

Well, you know what? My laptop still responds to the power button even when everything else has crashed -- it won't actually shut off, I have to rip the battery out of the back to accomplish that, but the disk access light goes on when I push the power button, so SOMETHING still happens.

So, by changing the "powerbtn.sh" script, I came up with a way to save the data. The laptop has a hard drive, and the script now forces all data from the Desktop directory over to a directory on that drive. X11 just crashed about 20 minutes ago on my machine, and so I was able to do a real-world test, and it worked. I have no idea if it will work every time, but at least it's SOMETHING. Tonight, it saved several hours of writing for a class paper due on Monday.

So, I'm back here to post it. Maybe it'll save someone else's data. Maybe Klaus will fix the startx script so that people can save their data manually. Maybe pigs will fly. Most likely, it'll disappear without a trace, but at least I'll have tried.

Thanks again for the Compiz fix. It's extremely useful to me -- I think it's the first time in a few years that I've gotten a useful answer off Knoppix.net. I appreciate it a LOT, and I appreciate your note above.

[utu]

@FlameWeasel

Thanks for the newsy notes.
I hope you will continue to participate and contribute to our forum.

I have turned off the my 'private' option since it has been used by
several in hopes I can solve their unique problems. More than likely
I can't, and the requestor would do better to ask in the open forum,
where others can see and respond to their problem.

If you are a competent scripter, many of us without formal training
can use some tutoring. Please help educate us. As for your needs
in Linux configuration, that's a common thread in which we all are
here looking for answers.

There are a few forum contributors which are too abrasive in their
inter-personal styles for my taste as well as yours. However, they
often have knowledge and/or experience we can learn from if we are
patient enough.

All things considered, I get more out of this forum than any other
I've run across. I do regret we don't have some participation by
Klaus K, himself. I imagine that he is a very popular and busy man
and hasn't the time to devote to this niche.

In keeping with this thread I offer the following update. I've turned
off Compiz, and I've turned back on the lxpanel hide-when-not-in-use.
I occasionally still have a keyboard lock-out that can only be
cured by control-alt-backspace. It only happens when I've also had
LibreOffice in use for spreadsheet operations. I can live with that.
I save my stuff fairly often, so I never lose much, if anything, on
an unplanned shutdown. And, finally, I can't see that the suggestion
in my Post #5 has any effect on any of my complaints whatsoever.

Looking forward to your powerbtn.sh thread.

[Forester]

Hi FlameWeasel,

I too hate questions that are not answered. Not because I ask a lot of questions but because I have many times found that someone has already asked exactly the same question and got no answer.

I decided to do something about that and stop whining that I had nothing to contribute because I'm only an embedded programmer. I decided to try to make sure every thread with a question posted on these forums gets an answer. I did it to see what trying to answer 'bad' questions could teach me about how to ask 'good' questions.

I know this pisses a lot of folk off because it sounds like I know everything. Believe me, I wise enough to know the more I learn the more I know I don't know. Sometimes an interesting question comes along to which I don't know the answer but I can use my experience to find out. I learn stuff, I help people and, if that browns people off sometimes, at least I have an excuse.

Posts by newbies with less than 10 (I think) posts are vetted before appearing on the forums.
This is an anti-spam measure. This entails a delay that is can be such that regulars who monitor "Today's Posts" don't ever see the question. One reason questions don't get answered is they drop down the list.

Forums are for user-to-user help. Most of the folk on this forum are not dead, they are just not geeks. Some questions are asked by folks who clearly know more than anyone else here. They tend not to get answers (that are of any use).

Many questions are asked by people with a Windows background (no offence intended) who are so used to the Microsoft definition of 'intuitive' that they just don't understand enough of what they are doing to phrase their question so that anyone can understand it. They tend not to get answers.

Some questions are actually rants by someone bent on compounding their own stupidity by making it public. For some reason they think everyone, in general, and KK, in particular, are responsible for their inadequacy. They tend not to get answers.

I find myself looking at questions and asking myself does this person merit the effort ? I ask myself does this person seem willing to learn or do they just want their problem to go away ? I ask myself is this person prepared to give (feedback) as well as take or are they just here for what they can get ? You can't tell with first timers, but with people who've been here before, it's a different matter.

Contribution to the forum of voluntary, No one has any right to expect an answer. No one who tries to answer a question has a right to expect feedback but polite feedback really does help.

The worst are the guys with a problem but already know everything and are able to dismiss every suggestion. They don't deserve answers.

On X-11

You seem to know an awful lot about memory leaks in X11 and I will take it that you know what you are taking about. It is a honour to learn from an expert.

If I were to say Windows 7 == SABENA I would mean the whole sorry Operating System. Most newbies might think X Windows or X server refer to the whole desktop experience when you and I know that it is only tiny part.

I am surprised to learn that the X server is (after 30 years still) flaky but the LXDE desktop (still very much 'in development') is not. I'm so glad utu's panel hiding problem isn't an LXDE issue after all.

One of the good things, they say, about Knoppix is it's hardware recognition and support.
It achieves this by using very recent kernels, the latest X server and all the latest drivers possible. Most accept that this may not be as stable at they wish. It seems we should expect better.

You mention nvidia cards. I don't know if you still have one. There is a constant stream of people come on here with a Dell this or a Dell that have video issues. I point them to the release notes on nvidia drivers that none of them have bothered to read. Most are grateful for the tip. They don't find ruling out the obvious before considering the obscure the least bit condescending.

You mention class papers. Perhaps you are a student. Even if you have been using X-11 since before you could walk you would have to be a very mature student to have been using it as long as I have. Your writing does not suggest maturity.

That leaves the possibility that you are some kind of teacher. Perhaps a xenophobe who can't stand the idea the a foreigner could come up with something as clever as Knoppix ?

I've been lucky enough never tp have had memory leak problems with the X server and I've not heard of them. So I learn something. I have had problem with X video drivers and the frustration of data loss that goes with them hanging. Most of the problems I have had have been with proprietary drivers. I avoid them and I will pay good money to not use a ATI/Radeon grahpics card at all under Linux. I know, totally irrational, but once burnt, twice shy.

You sound cross that Knoppix does not include proprietary drivers. You've a hard drive installation so no doubt you installed the proprietary driver yourself ages ago. I thought the main reason for preferring proprietary drivers over the open source ones is they have better support for 3-D acceleration needed for compositing. Yet you are so grateful to utu for telling everyone how to turn off Compiz, the compositing window manager. I learn something from this.

Myself, I have never turned Compiz off (other than out of curiosity). I managed to run Eclipse on a Knoppix machine with only 512 Kb RAM (and, thankfully, lots of swap space), with Firefox, Konsole, Konqueror and Kate at the same time. I never saw any evidence of a memory leak. Mind you this was at work so I never left it running for more than 8 hours at a time.

On Solution Spaces

As a teacher you understand problem spaces and solution spaces and that happiness lies in the intersection. Knoppix may be the Swiss Army Knife of Linux distributions but, heck, to use a Swiss Army Knife well you need to appreciate and respect its limitations.

I'm a programmer and I've been using Knoppix at work to program stuff. Knoppix is not meant for serious stuff like programming so I wouldn't recommend it unless you want to write programs for Knoppix and even them you should not write and test under the same instance of Knoppix. For me Knoppix was the best compromise I could come up with at short notice (and I mean compromise, not trade-off). I recognised and lived within its constraints.

I did not do a HD install. Knoppix is not meant for that. I've read recently that the HD install is only there to allow people to remaster Knoppix without needing to install some other Linux. People use HD install at their own risk. That's not smart arse, its hard nose.

Knoppix, even HD Knoppix, uses persistent store which you know has a higher write back latency that regular file systems. With Knoppix LiveUSB, the persistent store is usually on a FAT file system which is about as robust as a tin shack. To minimise the risk of loosing the lot, I rigged up my USB stick to boot off ext3 partitions.

Even then I only use the persistent store for configuration and stuff. Real stuff, like the programs I can't afford to loose are on another file system outside of the UNIONFS scheme of things and so are as good as with a real Linux HD installation like Debian.

I know shit happens. This way I don't wait until it has happened to do something about it.

On Knoppix Shutdown

A quick:


dpkg -l | fgrep knoppixshows that KK has contributed two dozen packages, mostly startup/shutdown or configuration scripts, to Knoppix and has altered only three himself. The vast majority of package come direct from the Debian repositories for which KK cannot be held responsible.

I am surprised to learn that KK's alteration of the "artwiz futuristic mouse cursor for x11" makes him responsible for memory leaks in the X server severe enough to give you problems.

Knoppix, as you know, has no display manager: when you exit the X window environment you don't get a new login screen. Knoppix shuts down. This is not a silly assumption in a start-up script but a deliberate design choice by KK and makes perfect sense for a LiveCD. An example of the solution space in which you have chosen to live when you installed to HD.

The shut down sequence of Knoppix flushes all pending disk writes and so should make sure the persistent store is up to date. From what you describe it seems this does not happen. Perhaps this is the price you pay for using a HD installation. Perhaps this is a bug in the Knoppix scripts but here is not the place to report it. KK does not read these forums. He does have a Debian mailing list and I'm sure would be very interested in your observations. Provided you are polite enough not to threaten his life, liberty or libido.

Thank you for the magic sys req reminder. You know all about it, which is amazing: I use it so seldom that I can't remember how to when I need to. I am suprised to learn that REISUB works before X Windows crashes but not after: I had been led to believe the magic sys req was independent of X windows. I shall refrain from making any smart arse suggestions.

Using the Power Button is neat. That's an interrupt and has nothing to do with the keyboard. I would like to try it but the X Windows on my Knoppix LiveUSB stubbornly refuses to crash. Perhaps you could tell us which WP you were using for your class paper ?

Oh, and of course you're welcome here. Bring the attitude and we can all have a good laugh. :)

[utu]

The original intent of this thread was to record my efforts
to cope with occasional X-crashes when using Knoppix 6.4.4.
I originally suspected LXDE, PCManFM, and Compiz as the
most likely culprits. I now believe those suspicions were
misplaced.

Prior to my Knoppix 6.4.4 experience, I'd used OpenOffice
virtually daily for years with no problems. Recently, I can
say I've used Knoppix 6.4.4 virtually daily for months.
I now have the strong feeling that any current video
problems I am having are best described as LibreOffice-related.
These problems seem to be described by others as crash-on save
or crash-on-close, are common to both LibreOffice and
OpenOffice, and for both spread-sheets and word processors.
In my cases, some prior cut-and-paste machinations usually
precede an 'outage'.

Bug reports I've seen don't give me any comfort that 'the
developers' have any ideas on what the problem might be.
I haven't even seen any work-arounds that I can recall.
In my case, control-alt-backspace returns my control, and
I don't think I've lost any data because of this nuisance.

Here's a complaint that seems typical enough:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=614182

[kl522]

Are you talking about X crash or a LibreOffice crash ? Totally different things altogether.

Even if LibreOffice application induces a X crash, it is still considered a X crash because under no circumstances a X server should crash.

[utu]

Greetings, kl522.

Thanks for your comments.
You make a good point concerning the semantics of this problem,
and that may be one reason I see no progress toward its solution.

Without giving the problem a name for the moment, the symptom
I observe and am plagued-by is the loss of keyboard control over
events on-screen. This keyboard lock-out occurs following some
spreadsheet activity, possibly including some cut-and-paste
transfers of data. An additional observation is that one of my
two cpus is in overload when this occurs. The lock-out occurs on
either 'close' or 'save' of the spreadsheet program. My instance
of this problem can be overcome merely with control-alt-backspace.
I don't think I have lost any data as a result of the interference.

Here are three bug reports that sound similar to my problem.
Two of these have 'crash' in the nominal title. I haven't found
any similar reports that focus on 'keyboard lock-out'.

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=614182

http://sourceforge.net/tracker/index.php?func=detail&aid=3262547&group_id=180858&atid=894869

http://ubuntuforums.org/showthread.php?p=10790951

[kl522]

Sorry to be particular with the semantics of the problem, but I believe you did not hit any X crash or X video problem - like I usually do with my intel video/graphics.

From what you have described, it would appear to be a LibreOffice issue. It will be interesting to note the high CPU usage is taken up by X or libreoffice applications - chances is that it's LibreOffice. Perhaps you want to upgrade the LibreOffice versions.

[utu]

@ Thanks for your comments, kl522.

As you probably already know, my setup is on a 2GB SanDisk.
If I look at all the changes Synaptic proposes for a small upgrade
of LibreOffice, I can just imagine the resultant crash if I try this.

So, I'm hoping Klaus K will come through with an all-new Version 6.5
which likely will include the LibreOffice upgrade. Although I must
say, none of the discussion of LibreOffice problems lead me to believe
that my particular problem is even being considered, let alone fixed.

[kl522]

Personally I don't think an all-new Knoppix version will be so soon. Klaus K has always has an "agenda" to his versioning ( though it is not a selfish agenda ), he likes to promote people to buy the Unix Magazine. For those who can wait, will probably wait. For those who can't wait, will probably have to seek alternative.

Perhaps you can consider a HD poorman install or invest in a bigger flash ? :)

[utu]

In going back over these notes, it occurs to me that I have
not checked out one 'obvious' possibility. One descriptor
I use for this problem is crash-on-close, or crash-on-save.

I save intermediate results sometimes several times daily
to a USB different than that which Knoppix is on. This
USB has about 13 Mb left out of 256 Mb total. Each save is
around 100 Kb. It might be that this may be one of the
culprits. Possibly the USB is showing wear & tear and/or
possibly it's too close to 'full' to allow for some necessary
USB machinations involved in saving results.

I've switched over to a larger USB for my results and we'll
see if this has any effect. I'd be very pleased to find that
the heart of the problem lies in the USB and/or its use to
save results and not in Knoppix.

I accept the idea of using a larger USB for Knoppix, and I do
have a 4 Gb device I can try, but I'd very much like to
understand the root cause of my difficulties first.