From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: [PATCH 1/1] Add virtio-input driver. Date: Fri, 20 Mar 2015 11:36:39 +0100 Message-ID: <1426847799.32097.66.camel@nilsson.home.kraxel.org> References: <1426756391-26585-1-git-send-email-kraxel@redhat.com> <1426756391-26585-2-git-send-email-kraxel@redhat.com> <1426844885.32097.36.camel@nilsson.home.kraxel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: David Herrmann Cc: virtio-dev-sDuHXQ4OtrM4h7I2RyI4rWD2FQJk+8+b@public.gmane.org, virtualization-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Rusty Russell , open list , "open list:ABI/API" , Dmitry Torokhov List-Id: linux-api@vger.kernel.org Hi, > > There will also be pass-through support, i.e. qemu > > opening /dev/input/event and forwarding everything to the guest. > > How should that be handled best? Copy all four from the host? Even > > though the bustype is BUS_USB? Not sure this actually improves things > > because the guest can match the device, or whenever this confuses apps > > due to BUS_USB being applied to virtio devices ... > > Lemme give an example: We have databases in user-space, that allow > applications to figure out the mouse DPI values of a device. Those > databases match on all four, bus+vid+pid+ver (sometimes even more, > like name and dmi). If one of those is not forwarded, it will not be > detected. Ok, so forward as much as possible. > I'd like to see all four forwarded from the host. I'd be fine with > "bus" being set to VIRTUAL, but I'm not sure why that would be a good > thing to do? I think for the emulated devices it's fine to use VIRTUAL. For the passthrough case suspected we could confuse apps because ->phys points to a virtio device whereas ->type says "I'm usb". But at least the device database probably doesn't care much about the physical path I guess, because the mouse is the same no matter which usb port I plug it in, correct? cheers, Gerd