From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MrDDa-000382-DA for qemu-devel@nongnu.org; Fri, 25 Sep 2009 12:00:22 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MrDDV-00034d-Pe for qemu-devel@nongnu.org; Fri, 25 Sep 2009 12:00:21 -0400 Received: from [199.232.76.173] (port=37691 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MrDDV-00034X-Dw for qemu-devel@nongnu.org; Fri, 25 Sep 2009 12:00:17 -0400 Received: from mail-yx0-f173.google.com ([209.85.210.173]:53223) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MrDDV-0000TM-0h for qemu-devel@nongnu.org; Fri, 25 Sep 2009 12:00:17 -0400 Received: by yxe3 with SMTP id 3so679671yxe.4 for ; Fri, 25 Sep 2009 09:00:15 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <87iqf72mqm.fsf@pike.pond.sub.org> References: <1253611767-6483-1-git-send-email-kraxel@redhat.com> <1253611767-6483-11-git-send-email-kraxel@redhat.com> <8763b8b1dh.fsf@pike.pond.sub.org> <4ABC7503.70200@redhat.com> <87iqf72mqm.fsf@pike.pond.sub.org> From: Artyom Tarasenko Date: Fri, 25 Sep 2009 17:59:55 +0200 Message-ID: Subject: Re: [Qemu-devel] [PATCH 10/13] Implement scsi device destruction Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Gerd Hoffmann , qemu-devel@nongnu.org 2009/9/25 Markus Armbruster : > Gerd Hoffmann writes: > >> =A0 Hi, >> >>> If I understand this correctly, SCSI devices "overwrite": if you add a >>> new one with an existing SCSI ID, the old one gets disconnected >>> automatically. =A0Isn't that inconsistent with other buses? =A0PCI, >>> specifically. =A0Question applies before your patch already. >> >> Yes, this is correct. >> I've just maintained current behavior. >> >> To extend that question: =A0While playing with that I've noticed linux >> does not automagically find the a scsi disk hot-plugged in. =A0After >> reboot (and the scsi bus rescan triggered by that) it finds the >> disk. Reloading the driver module probably would have worked too. =A0We >> don't signal the guest in any way it got a new disk, so this isn't >> exactly surprising. =A0Is this just a emulation limitation? =A0Or a >> limitation of the emulated scsi host adapters? > > What appens when you hotplug or just switch on a real SCSI device? =A0Doe= s > Linux pick it up automatically? =A0Long ago when I last tried that, I > think I had to do a magic write to sysfs to make it look for the device. I guess it wasn't magic, but an official way of doing it. At least SCSI-2 controllers didn't get any notification signal on a hot-plug. I used to do it with echo "scsi add-single-device 0 0 3 0" > /proc/scsi/scsi