[blfs-support] Missing cursor in text (console) mode

Bruce Dubbs bruce.dubbs at gmail.com
Mon Mar 18 16:46:23 PDT 2013


alex lupu wrote:
> Hello,
>
> (B)LFS i686-pc-linux-gnu
> kernel 3.8.2 (can be anything)
> Two SSD Intel drives, identical system/software-wise (one is a "clone" of
> the other):  the 120G "320" and "520" models, respectively.
>
> PROBLEM
> After boot-up I have the console cursor on one drive (520) and I don't
> on the other (320).
> Mind boggling.
>
> DETAILS
> 1. The "system" behavior is otherwise absolutely the same no matter which
> drive I boot off of (like I said, the drives are software, size, partitioning,
> etc., identical).
>
> 2. One drive (520) is nominally FASTER (more recent model) than the other.
> NOTE:  This leads to my suspicion as to the cause;  some timing race somewhere
> in the innards of the "bad" drive (320).
>
> 3. On boot-up my system enters runlevel 3  ("id:3:initdefault:").
>
> 4. A relevant (important, I think) excerpt from my console display
>     during boot-up:
>
>   ...
>   INIT: version 2.86 booting
>
>                          Welcome to Linux From Scratch
>                     Press 'I' to enter interactive startup
>
>   tsc: Refined TSC clocksource calibration: 3400.023 MHz
>   Switching to clocksource tsc
>   AT THIS POINT, a 5 sec. pause, based on my site "itime" for "Press 'I' to ..."
>     *  Mounting virtual file systems: /run /proc /sys /dev    [  OK  ]
>    ...
>
> 5.
> THE MAJOR DIFFERENCE between the behavior of the two drives:
>   - 520:  on the console display line identified as "AT THIS POINT" above,
>    the cursor comes up (blinking).  I.e., the cursor is already _active_!
>   - 320:  on the same console display line identified as "AT THIS POINT" above,
>    there is no cursor (an will never show up, as the subject of this post
>    discusses and puzzles)
>
> REFERENCES
>   FWIW, the two "clocksource" messages above come from
>   arch/x86/kernel/tsc.c:  "Refined TSC clocksource calibration: ..."
>   kernel/time/clocksource.c:  "Switching to clocksource ..."
>
> COMMENT
> The problem is no life-threatening, I can easily, once I log-in (or in a
> script) restore the cursor on all screens (Alt-F1, ... Alt-F6) but
> mild as it appears, it's of the painful scratch-your-head, puzzling type.
> And it SHOULDN'T happen.

It does sound like a timing/hw issue of some kind.  Does it happen if 
you are not using an interactive boot (IPROMPT comments out)?  Are you 
using a framebuffer?

   -- Bruce






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