On 03/27/2013 06:13 PM, Hans de Goede wrote:
Hi,
On 03/27/2013 04:33 PM, Uri Lublin wrote:
On 03/25/2013 12:17 PM, Hans de Goede wrote:
Hi,
Hi Hans,
Thanks for reviewing.
On 03/25/2013 11:01 AM, Uri Lublin wrote:
rhbz#842816
It seems that sometimes a USB device's bus.address is changing after
installation of WinUSB driver for that device.
So instead use vid:pid which are consistent across driver
installation.
The switch to using vid:pid is done in patch 8/9.
Some code reuses variables named "bus" and "address" to hold vid
and pid
values. If people think this should be changed to new variables
names (ifdefed)
and/or new function instead of
spice_usb_device_manager_get_udev_bus_n_address
let me know.
Using two devices with the same vid:pid on the same Windows client
is already
not supported, since Windows installs USB drivers for specific devices
based on their vid:pid
Hmm, I'm not very happy with the approach you've chosen here. Just
because
usbclerck / our driver swapping magic currently does not support
having devices
with identical vid:pid is not a good reason to add the same problem
to other
parts of the code. The contrary is true really, this is something
which we
should try to fix, not make worse.
I'm only trying to fix the Windows bus.addr inconsistency problem.
I don't think that makes things worse, but better.
I agree that this patch-set inserts the existing driver limitation
(of using two devices with the same vid:pid) into spice-gtk,
for Windows (and keeps Linux as is).
This limitation already exists for Windows clients, and
we can remove it from spice-gtk in the future if needed.
Ok, so lets split the discussion in 2:
1) What do we need today
Today we need a way to work around the bus.addr pair not being stable
for a single device under Windows, since today we already do NOT
support using multiple devices with the same vid:pid, using vid:pid
(iow this patchset) would be an acceptable solution, but only today!
great.
2) Where do we want to be tomorrow
"Tomorrow" we will hopefully be using filter drivers, and hopefully
then we don't need the whole driver install dance (even for new devices
which were never plugged in before?), and then we can remove a whole
bunch of windows specific "murk" from the spice-gtk code for usb
handling.
Yes, we want to use a filter driver which needs to be installed only once,
and works for all/more USB devices. We wanted filter driver from
the start, but it was not in good enough a condition.
Once we can use a filter driver, we can remove all the code
that asks usbclerk to install the driver for specific devices
(and of course we will not need usbclerk at all anymore)
So if we can agree on this being a temporary thing, then I can agree
with the vid:pid approach *for now*, but this really really needs to
be replaced / fixed in the near future.
I agree. Once the filter driver is good enough we'll switch to using it.
When using a filter driver we can identify devices with bus.addr
on Windows too.
So with this clear, and assuming you will agree, let me actually really
review this patch-set :)
Thanks.
Some remarks on alternative approaches below, but lets just go with
vid:pid for now.
<snipped>
bus.addr is 100% reliable on Linux, replacing it with bus + port-path
introduces the issues we're having on Windows without any gains (other
then
unification of the code.
Hopefully with the filter driver, bus.addr is going to be reliable for
Windows too.
Thanks,
Uri.
_______________________________________________
Spice-devel mailing list
Spice-devel@xxxxxxxxxxxxxxxxxxxxx
http://lists.freedesktop.org/mailman/listinfo/spice-devel