Re: More data on ide-cd "playing music" death

Jens Axboe (
Wed, 02 Dec 1998 18:19:52 +0100

Romano Giannetti wrote:
> > Do you have anything else on the secondary controller? Did the system
> > respons to any of the other sysrq's, specifically sysrq+p? This might
> > indicate that Andre's suggestion regarding variable timeouts would
> > be useful. I hope to get my hands on a "newer" CD-ROM so I can do
> > some testing on my own.
> No and no, respectively; cdrom is the only device on hda1, and system
> seemed dead. I was in X, so I cannot say if a) SysRq-p was not
> working, or b) it was working and simply the klogd/syslogd could not
> access disks. I could try to lock the system without X, later, before
> going home (I have a deadline for a paper and ... I need latex up and
> running :).

Well, I can't compete with a pending paper so I'll just have to wait
until you can trigger the bug and get some output from sysrq :). I
thought your CD-ROM was on hdc?

> > > interrupt we report a lost one. Is it possible (wild guess) that
> > > simply we forgot to increment/decrement/unlock something?
> >
> > Andre, what do we currently do with a lost interrupt?
> I noticed that sometime in ide-cd.c we do a cdrom_end_request(), and
> sometime not. What I was thinking (please bear with me, I really did
> not understand the code) is that: if in ide.c, in ide_timer_expiry(),
> we trigger
> if(drive_is_ready(drive)) {/*lost interrupt*/}
> than with handler(drive) I think we end calling cdrom_pc_intr(); now,
> if nothing is done to "ack" the new situation, at the next timer
> expiration we have a ready drive, no interrupt, and so on... well I'm
> saying idiocies, probably :), so I shut up.

handler(drive) ends up in cdrom_pc_intr -> cdrom_decode_status and
finally cdrom_end_request. I'll dig deeper into this tomorrow, when
time hopefully permits it.

> Romano

*  Jens Axboe <>
*  Linux CD-ROM Maintainer
* "The only thing that interferes with my
*  learning is my education." -- A. Einstein

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