is magicdev evil?

[Owen Taylor]

On Mon, 2003-10-06 at 16:57, Tommy McNeely wrote:
> I personally think magicdev is kindof evil... it was just recently wasting
> away at like 25% of my CPU, and my CDROM drives haven't been opened in
> like a week. What does it do? is it only for mounting CD's or does it also
> mount removable media (like the slot in the side of my printer)? I always
> find myself killing it and rpm -e'ing it.. just wondered what it is
> supposed to be used for and whether or not we might find a replacement.
> Don't CDROMS send some sort of "signal" when they are opened/closed that
> would be better than constantly probing it?

Basically:

 A) If magicdev is eating 25% of your CPU, something is going wrong,
    and you shoudl file a bug so we can fix it. It isn't supposed
    to do that.

    There was a kernel bug recently in this area, but unless your
    /var/log/messages is getting filled with lots and lots of junk,
    that's not it.

    You should file a bug with a) any messages that are appearing
    in /var/log/messages b) a short snippet of the strace of magicdev
 
     killall magicdev
     strace -o /tmp/magicdev.log magicdev 
     <wait 20 seconds>
     <control-c>
    
    c) The contents of /proc/ide/hdc/model (modify as appropriate
    if your cd-rom is elsewhere.)
    
 B) No, CDROMS do not reliably send a signal when they are opened
    and closed. There are things in the spec for that, they are not
    implemented uniformly.

    There may be better things to do than what magicdev does. They
    probably would require full-time work for about a month for a
    pair of a test engineer and a developer to get going and make
    reliable.

    (Basically, you have to have a big list of hardware with 
    information on what works where.)

Regards,
					Owen