From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Peter Lieven <pl@dlh.net>,
dlaor@redhat.com, Gerd Hoffmann <kraxel@redhat.com>,
Markus Armbruster <armbru@redhat.com>
Subject: Re: [Qemu-devel] Disable PS/2 mouse
Date: Thu, 10 Jun 2010 13:15:31 +0100 [thread overview]
Message-ID: <201006101315.33801.paul@codesourcery.com> (raw)
In-Reply-To: <4C10952B.6090202@redhat.com>
> For usb hid devices: No idea how they work and whenever we can put them
> into sleep somehow (with/without guest cooperation).
The issue with USB is that it is (by design) a polled system. The UHCI adapter
has to wakeup every 1ms to read transfer descriptors from guest RAM.
Until recently there was a bug in the UHCI emulation that would wake the guest
even if the tablet NACKed the poll.
See http://lists.nongnu.org/archive/html/qemu-devel/2010-04/msg00150.html
USB does support "autosuspend". This allows a guest to put a device to sleep,
and have it wake up when something interesting happens. In theory this
includes HID devices. However I believe linux disables it because there's so
much broken hardware out there that implements it incorrectly. I suspect qemu
does not currently implement this feature either.
Paul
prev parent reply other threads:[~2010-06-10 12:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-08 12:49 [Qemu-devel] Disable PS/2 mouse Peter Lieven
2010-06-09 7:55 ` Markus Armbruster
2010-06-09 8:24 ` Peter Lieven
2010-06-09 11:27 ` Markus Armbruster
2010-06-09 8:27 ` Peter Lieven
2010-06-09 8:51 ` Mark Cave-Ayland
2010-06-09 10:52 ` Gerd Hoffmann
2010-06-09 11:05 ` Peter Lieven
2010-06-09 13:46 ` Peter Lieven
2010-06-09 14:35 ` Gerd Hoffmann
2010-06-10 7:12 ` Dor Laor
2010-06-10 7:32 ` Gerd Hoffmann
2010-06-10 10:35 ` Peter Lieven
2010-06-10 12:15 ` Paul Brook [this message]
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