From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MQX2P-0004JI-Mh for qemu-devel@nongnu.org; Mon, 13 Jul 2009 21:42:33 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MQX2L-0004DF-4n for qemu-devel@nongnu.org; Mon, 13 Jul 2009 21:42:33 -0400 Received: from [199.232.76.173] (port=56008 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MQX2K-0004Cu-UT for qemu-devel@nongnu.org; Mon, 13 Jul 2009 21:42:28 -0400 Received: from main.gmane.org ([80.91.229.2]:49273 helo=ciao.gmane.org) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MQX2K-0000PK-Ge for qemu-devel@nongnu.org; Mon, 13 Jul 2009 21:42:28 -0400 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1MQX2G-0001lr-7A for qemu-devel@nongnu.org; Tue, 14 Jul 2009 01:42:24 +0000 Received: from 75-54-218-43.lightspeed.mlpsca.sbcglobal.net ([75.54.218.43]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 14 Jul 2009 01:42:24 +0000 Received: from subhraveti by 75-54-218-43.lightspeed.mlpsca.sbcglobal.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 14 Jul 2009 01:42:24 +0000 From: "Dinesh Subhraveti" Date: Mon, 13 Jul 2009 18:42:01 -0700 Message-ID: References: <04b201ca0411$514a9d40$732d2b09@DineshThinkpad> <4A5BDB00.8030100@codemonkey.ws> Sender: news Subject: [Qemu-devel] Re: [PATCH] No keyboard / mouse after reboot List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org "Anthony Liguori" wrote in message news:4A5BDB00.8030100@codemonkey.ws... > Needs a Signed-off-by. However... > > Dinesh Subhraveti wrote: >> At system initialization, some guests conclude that i8042 controller is >> missing when the PS2 buffer is full. As a result, the guest comes up >> with no keyboard or mouse. The behavior is seen when the user types or >> mouses over the VNC window during the BIOS phase of a reboot, causing the >> PS2 buffer to fill up. It doesn't occur when the system boots the first >> time, since the device is initially disabled and doesn't accept events. >> This patch tunes Qemu parameters to reasonable values which make the >> guest happy. Linux assumes the size of PS2 buffer to be 16 bytes, while >> Qemu defines it as 256. Reducing PS2_QUEUE_SIZE to 15 ensures that the >> guest never sees the buffer to be full. > > Why is Linux making assumptions about queue size being 16? It sounds Good question, for which I don't know the answer. But regardless of the buffer size, it fills up quite quickly with mouse events, and the guest would be left without a keyboard. > broken to me. In fact, I looked in one of my PC hardware books and it > claims that the typical KBD buffer size is around 20 bytes so if Linux is > assuming 16, it's definitely broken. > > But there's speculation in the previous thread that we're masking a BIOS > bug. Has that been ruled out? > Yeah, this doesn't seem to be a BIOS issue. It is also reproducible with -kernel option. Thanks, Dinesh