Date: Thu, 30 Sep 2010 20:46:11 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Andriy Gapon <avg@icyb.net.ua>, FreeBSD-Current <freebsd-current@freebsd.org> Subject: Re: letting glabel recognise a media change Message-ID: <4CA4CCE3.9060408@FreeBSD.org> In-Reply-To: <mailpost.1285845776.1043534.73790.mailing.freebsd.current@FreeBSD.cs.nctu.edu.tw> References: <4CA3BD7C.9080306@feral.com> <mailpost.1285845776.1043534.73790.mailing.freebsd.current@FreeBSD.cs.nctu.edu.tw>
next in thread | previous in thread | raw e-mail | index | archive | help
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. And even without AN support it would be nice to implement proper handling for SCSI "UA - media changed" errors within CAM. It still won't be perfect without using polling, but probably still something. -- Alexander Motin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4CA4CCE3.9060408>