Re: cdrom_id (udev) causes "No disk in drive" warning for ide devices with removable media

[Kay Sievers <kay.sievers@vrfy.org>]

On Thu, Sep 15, 2005 at 12:34:47AM +0200, Thomas Heinz wrote:
> You wrote:
> > > Interestingly, I found out that the kernel message is generated on
> > > close(fd) (line 151).
> >
> > Hmm, no idea. I tested it remotely on a few boxes with a SCSI cdrom
> > and none of them prints anything on a cdrom_id run.
> 
> On close(), scsi_set_medium_removal() is called which again calls  
> ioctl_internal_command(). The scsi request is initiated here:
> http://lxr.linux.no/source/drivers/scsi/scsi_ioctl.c#L109
> It "returns" NOT_READY which effectively causes the kernel message.
> 
> In order to avoid the message during bootup, I have defined some rules 
> before the default rule set which mimic the effect of executing cdrom_id 
> without actually doing it. The execution of the default rule set for the 
> specific scsi device is avoided by the last_rule option.
> 
> Since only one of my scsi cdrom devices behaves like this (and moreover you 
> could not reproduce the behaviour), it is probably not a general problem. 

Hmm I wouldn't call it a "problem". It's just a message from our noisy
kernel. :)
I don't see a nice way to prevent that from userspace. We just asks the
device to identify itself, which should not trigger media validation.
Don't know if there is a trick we don't know about now.

> What do you suggest to further track the problem down?

The benefit of a lot of kernel messages for things like this is really
questionable. Maybe the firmware in your device has some weird behavior.
Unfortunately, I don't know how to debug this and I better go fix some of
the real bugs we have. :)

Thanks,
Kay


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