FC3 can no longer successfully burn CDs]

[Fulko Hew]

Here is an update to my investigations on why I can no longer
burn good CDs on FC2 and FC3. (Bugzilla # 141884)

Background: 

  With post 2.6.7 kernels, CDs that are burned, cause
  read errors at semi-random sectors.

Current observations and investigation process:

  After reading about people having problems with audio
  'hickups' (bugzilla #143421) I was reminded of some 'hickups'
  I've been hearing lately.  Upon further investigation,
  it turns out that those dropouts were on the original
  mp3, since they always happened at the same spot.

  But that got me to thinking about what happens when I burn
  CDs...

  a) I use a screensaver called "Euphoria" an OpenGL, fairly CPU
     intensive application.
  b) Burning CDs takes a while, and my screen saver always kicks
     in. (because I'm usually doing something else on another
     machine while waiting.)

  So I decide to persue testing on FC3.  I won't bore you with all
  the tests I did over the 25 hours of testing and countless burns.
  But here are the results (and they uncover another error too).

  1/ The timer on the screensaver does not work.
     - Time values < 20 minutes are obeyed.
     - Time values >20 minutes always results in a timeout of 20 minutes.

  2/ When the screen save kicks in, the CD burn process causes a burn failure.

  3/ There is no indication on 'cdrecord' of burn errors.
     (Burnproof is on, but never used, and min buffer fill was 84%.)

  4/ It is independent of actual screen saver selected.
     (I also tried 'blank screen'.)

  5/ The semi-random location of the read error was caused because
     of the varying screensaving time I had configured, or other
     keyboard activity that deferred screen timeouts.

  6/ Continuous keyboard usage during burning (deferring screen timeouts)
     results in good burns.

  7/ Disabling screen saver results in a good burn (FC3 only, see item 9 below).

  8/ It doesn't seem to be related to the 'inform power management
     about screen blanking' option.


  9/ Disabling screen savers on _FC2_ does not work.  In addition to
     observation #1 above, if the screen saver is disabled, the screen
     will still blank after a maximum of 20 minutes.


Conclusions:

    i/  Screen saving timer misbehaves (different symptoms on FC2 versus FC3).

   ii/  Screensaving induces CD burn errors.

  iii/  A good burn (when read) will read extra data past the sixe of the
        original ISO written (15 x 2048 bytes)

Note: The original CD error was reported as bugzilla # 141884.
      I think the original bugzilla should be split into multiple
      reports.  I will do this later today.