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Re: [Qemu-devel] udev 42-qemu-usb.rules considered harmful?
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] udev 42-qemu-usb.rules considered harmful? |
Date: |
Wed, 17 Oct 2012 12:58:19 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:10.0.8) Gecko/20121012 Thunderbird/10.0.8 |
Hi,
> But the mouse is jumpy anyway. I guess one can get used to this
> behavour, given the tradeoff and that the behavour is not VERY annoying --
> it is annoying, but just for a "bit", it feels like old mechanical
> mouse with bad sensor or dirty ball when you can move the mouse but
> cursor sometimes stays in place and sometimes moves, depending on
> the surface and direction of the move... ;)
How long are the delays for you?
> What happens when the (device, bus) is suspended? Does host still
> sends interrupts periodically (but with much lower frequency)? Or
> is it the bus/hub/device which should signal attention at some point?
UHCI raises an IRQ, guest restarts USB bus in response. Which takes a
bit of time, so the first mouse event of an idle tablet takes a little
bit longer. As far I know linux schedules the first poll a bit in the
future, so this could be where the delay comes from.
Do you also see delays with xhci? (-device nec-pci-xhci -device
usb-tablet) ?
cheers,
Gerd