Testing CAM wrapper for ata(4) controller drivers

Juergen Lock nox at jelal.kn-bremen.de
Sun Dec 13 00:14:23 UTC 2009

In article <4B20EDD2.5000102 at FreeBSD.org> you write:
>Andriy Gapon wrote:
>> on 10/12/2009 01:07 Alexander Best said the following:
>>> ah. i see. thanks for the hint. sorry mav for blaming ATA_CAM. ;) would be
>>> nice if this would be fixed at some point. i believe the problem also applies
>>> to tape drives, usb memory card readers, etc.? so generally speaking: any
>>> devices which allow new media insertion, but don't disconnect/re-attach
>>> from/to CAM.
>> Yes, we need to get some notification that media is changed and then trigger geom
>> action.  Right now there is no notification from hardware in most cases and there
>> is no support for handling that in drivers, AFAIK.  Maybe ahci driver starts to
>> add support for that.  So either something needs to poll media for changes or a
>> user has to trigger some action explicitly.  No magic.
>Both ahci and siis drivers already have SATA Asynchronous Notifications
>support, that was especially made to do that. Now AN used to receive
>messages from PMP about fan-out ports physical events and working fine.
>What is needed: SATA ATAPI device with AN support (haven't checked if
>there are ones on the market), enable these messages, improve cd driver
>to make some useful activity (have no idea how) on such events.

Doesn't scsi have `unit attention' to notify media changes?  Or does
that not work as expected with atapi?

 Just wondering... :)

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