letting glabel recognise a media change

Alexander Motin mav at FreeBSD.org
Thu Sep 30 21:00:54 UTC 2010

Andriy Gapon wrote:
> on 30/09/2010 20:46 Alexander Motin said the following:
>> Andriy Gapon wrote:
>>> on 30/09/2010 01:28 Matthew Jacob said the following:
>>>> If something like that was in place, I assure you that things would start to use
>>>> it very quickly.
>>> I am not sure about this.
>>> Because, e.g. I don't see an easy way to know that media is changed in scsi_cd
>>> driver.  That is, without polling.  I don't consider polling to be an easy way for
>>> a number of reasons.
>> SATA specification defines concept of Asynchronous Notification. It is
>> already used by port multipliers to report about PHY events. It is also
>> supposed to be used by CD drives to report media change. I haven't seen
>> such devices yet, but hope they may appear sometimes.
> Would this require some reverse-path from SIM driver to peripheral driver to
> deliver a notification?  Do we have one?

Yes we do. SATA PMP driver (it looks like usual peripheral driver from
this point) already receives and handles AC_SCSI_AEN messages sent to it
via xpt_async() mechanism.

Alexander Motin

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