cvs commit: src/sys/dev/ata atapi-cd.c atapi-cd.h

[Scott Long]

Poul-Henning Kamp wrote:
> In message <473DCF61.6010107 at samsco.org>, Scott Long writes:
> 
>>> What I've sortof talked phk into is that if I return the "right" error 
>>> code in the "start" function, it will back off and not retry nor chatter.
>>> We still need the "access" function to return OK if HW present or we 
>>> cannot send ioctl calls to an empty drive.
>>>
>> IMHO, overloading g_start just adds more cruft to the problem.
> 
> The fundamental problem is that the CDROM ioctls don't distinguish
> between drive and media.
> 
> In a nutshell: we are forced to let the open succeed, so the ioctl
> to close the tray can be issued, before we can get at the media.
> 
> The problem with letting the open (aka g_access) succeed, is that
> the GEOM tasting starts.
> 
> Redefining the ioctls is not a realistic option at this point, so
> the task is to find a workaround for the API-deficiency.
> 
> What sos@ and I talked about is that we need to have an error return
> that says "The drive is here, but there is no media", to fail the
> tasting without GEOM reporting I/O errors on the console.
> 
> The simplest way to do this, is probably to overload ENOENT or some
> other currently undefined errno for this effect.
> 

But then why not have g_access be able to communicate the ability to 
access the device independent from the ability to access the media?
Seems like both of these questions are "access" questions.

Scott