https://bugzilla.novell.com/show_bug.cgi?id=579932
https://bugzilla.novell.com/show_bug.cgi?id=579932#c14
Andreas Nordal changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
CC| |andreas_nordal_4@hotmail.co
| |m
Version|RC 2 |Final
Resolution|WORKSFORME |
Severity|Major |Critical
--- Comment #14 from Andreas Nordal 2010-08-24 19:07:10 UTC ---
Reopening because audio/video playback also hangs in the final version of
OpenSuSE 11.3. In fact, my testing shows that _any_ real-time program _will_
eventually make the scheduler seem to hang if run long enough.
The bug appears at least with kernels 2.6.34-12-desktop and 2.6.34-12-vanilla
provided by OpenSuSE repos. I was unable to boot with 2.6.31-rc8-rt9-6-rt.
These kernels have been untainted by proprietary drivers; I am using nouveau
exclusively.
I have not tested any release candidates, but this is at least a regression
since 11.2. Specifically, in 11.2, the hang randomly occured during boot,
shutdown and suspend to RAM (suspend to disk never worked for me), whereas in
11.3, the hang occurs when the computer is on.
Once the computer hangs, it hangs forever, until I do one of the following:
- press or release any key except the Fn key
- move the mouse cursor
- right/left-click with the touchpad
- plug or unplug AC power
- switch on/off the rf-killswitch (the WiFi button)
Plugging or unplugging the ethernet cable did not have any effect.
My computer was able to hang 9 hours without making any progress during the
installation; it would probably still do so, hadn't I interrupted it.
I have observed that the hang will eventually occur during:
- playing video: Sounds like it hangs and resumes a hundred times per second,
before it randomly stops resuming. Executing ´yes´ simultaneously makes it play
smooth without hanging.
- playing audio: The login sound of KDE is partially repeated infinitely (a
symptom of http://en.wikipedia.org/wiki/Buffer_underrun#Multimedia_playback)
- downloading: webbrowsing, using zypper, updating in the process of
installation
- blinking text in the terminal
- blinking cursors in various programs
- the screensaver
IO bound or CPU bound tasks do not seem to trigger the hang. Only tasks that
are frequently sleeping.
I made a test program that repeatedly calls clock_nanosleep (alternatively
sleep and usleep), like any real-time program does. Empirically, it seems that
these function calls have a certain probability of hanging the kernel - short
and frequent sleeps or many instances of the running program, and the kernel
hangs sooner. When run as root, the program will succeed to acquire the highest
priority with FIFO policy and lock its memory in RAM, but still hangs (perhaps
less frequently). In other words: Since this program cannot meet its deadlines,
nothing can! Conclusion: The scheduler does not work properly on my computer.
My computer is a laptop (Multicom Compal IFL90+):
Intel Core 2 Duo T8100
Nvidia GeForce 8600M GT
Intel PRO/Wireless 4965 AGN
Broadcom NetLink BCM5787M Gigabit Ethernet
What else do you need to know?
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