From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:55701) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOPC8-0007JF-Td for qemu-devel@nongnu.org; Wed, 17 Oct 2012 04:41:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TOPC3-0002v5-34 for qemu-devel@nongnu.org; Wed, 17 Oct 2012 04:41:40 -0400 Received: from isrv.corpit.ru ([86.62.121.231]:37560) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOPC2-0002tf-SJ for qemu-devel@nongnu.org; Wed, 17 Oct 2012 04:41:35 -0400 Message-ID: <507E6F32.4070009@msgid.tls.msk.ru> Date: Wed, 17 Oct 2012 12:41:22 +0400 From: Michael Tokarev MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] udev 42-qemu-usb.rules considered harmful? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel , Gerd Hoffmann Hello. I noticed that "some" versions of linux guests shows quite bad behavour of mouse cursor: it freezes after some idle time, and when you move mouse, it jumps after some delay to rather distant position. So, mouse becomes "freezy/jumpy", so to say. Quite some painful debugging pointed to the following udev rule: ---- /lib/udev/rules.d/42-qemu-usb.rules ---- # # Enable autosuspend for qemu emulated usb hid devices. # # Note that there are buggy qemu versions which advertise remote # wakeup support but don't actually implement it correctly. This # is the reason why we need a match for the serial number here. # The serial number "42" is used to tag the implementations where # remote wakeup is working. # ACTION=="add", SUBSYSTEM=="usb", ATTR{product}=="QEMU USB Tablet", ATTR{serial}=="42", TEST=="power/control", ATTR{power/control}="auto" ---- end ---- (And a few other similar rules, for other QEMU USB devices). Removing this rule restores correct mouse behavour. As far as I can see, this rule is to reduce polling interrupt frequency, but apparently it does not help: any usb device connected to guest, and the host CPU usage rises anyway, with or without this rule. Now the question: should we remove this rule? Why it is needed to start with? (qemu version 1.1, but the same bad behavour happens with other versions too). Thanks, /mjt