kern/81496: acd (atapicd) device lacks devstat

Andriy Gapon avg at
Thu May 26 12:00:11 GMT 2005

>Number:         81496
>Category:       kern
>Synopsis:       acd (atapicd) device lacks devstat
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu May 26 12:00:06 GMT 2005
>Originator:     Andriy Gapon
>Release:        5.4-RELEASE
5.4-RELEASE i386
6.0-CURRENT i386
acd device does not register itself as a geom disk with create_disk()
Soeren said a long while ago that there are some reasons for that:

I am not sure how valid those reasons are, because cd device is a geom disk and it essentially implements very similar interface although for a different bus.

I don't want to venture further in acd vs. geom disk situation, but not being a geom disk acd doesn't have get automatic devstat bookkeeping (as cd, ad etc do). It doesn't have any devstat bookkeeping of its own too.

On a system with ATAPI CDROM and atapicd device in kernel do the following:

1. sysctl kern.disks - acd* won't show up in the list returned
2. iostat -d - acd* won't be there
3. inspect atapi-cd.c sources
sorry, no patch at this time

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