From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: Re: [PATCH V4 3/7] libxl: add pvusb API Date: Tue, 16 Jun 2015 12:11:19 +0100 Message-ID: References: <1433906441-3280-1-git-send-email-cyliu@suse.com> <1433906441-3280-4-git-send-email-cyliu@suse.com> <557EE03F.5040108@suse.com> <557F18E8.8050305@suse.com> <557FFFA9.2070002@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <557FFFA9.2070002@suse.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Juergen Gross Cc: Wei Liu , Ian Campbell , Ian Jackson , Chunyan Liu , "xen-devel@lists.xen.org" , Jim Fehlig , Simon Cao List-Id: xen-devel@lists.xenproject.org On Tue, Jun 16, 2015 at 11:51 AM, Juergen Gross wrote: >> The "busid" interface that Chunyan is describing requires the caller >> to find out that long name -- 2-3.1.2 -- rather than the traditional >> short name (002:010). Just accepting "2-3" is not sufficient. > > > qemu with my patch will find the device only if the long name is used. > So the "port" in qemu would be "3.1.2" in your example above. Ah, right -- sorry, looking at the patch I saw that "port" was converted using strtoul, but now I see that was "bus", and that "port" is a string. That's what I was missing. > BTW: be careful with the syntax: x:y is used by qemu to specify a device > by vendorId:productId, you should write "002.010" to use the short name > above. Yes, thanks for the reminder. I knew there was some way to distinguish bus.addr and vendor:device, but I'd forgotten the exact semantics. So as Juergen says, the typical way to write these would be: - bus-port; e.g., 2-3.1.2 is bus=2, port=3.1.2. Stable in topology, not in device - bus.addr: e.g., 2.10 is bus=2, address=10. Unique every time a device is plugged in (so no risk of aliasing, but not stable across reboots) - vendorid:deviceid: e.g., 1050:0111 is vendorid=1050, deviceid=0111. Stable on device class (so same no matter when or where you plug it in, but can't tell two identical devices apart). -George