Testing CAM wrapper for ata(4) controller drivers

Alexander Motin mav at FreeBSD.org
Thu Dec 10 12:47:20 UTC 2009

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.

Alexander Motin

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