Dmitry Torokhov schrieb:

On 3/28/07, Jiri Kosina [off-list ref] wrote:

quoted

On Tue, 27 Mar 2007, Thomas Meyer wrote:

quoted

It seems, that after the resume all usb devices gets removed and

plug in

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again (virtually!). This results in a new input device name:

Yes, this is what actually happens. JFYI see current thread on lkml
which
is a bit realted - http://lkml.org/lkml/2007/3/27/149 if interested.

quoted

This change confuses the X synaptics driver:
Touchpad no synaptics event device found (checked 11 nodes)
Touchpad The /dev/input/event* device nodes seem to be missing
(EE) xf86OpenSerial: Cannot open device /dev/input/event2
        No such file or directory.
(WW) Touchpad: cannot open input device
One could say that the synaptics driver rightly complains about the
missing event2 device! So is this a bug in the X synaptics driver?

You can of course work this around by adding an udev rule such as

SUBSYSTEM=="input",KERNEL=="event*",SYSFS{name}=="appletouch",SYMLINK+="input/appletouchpad"


and the let Xorg use /dev/input/appletouchpad, which will always be a
symlink to the correct device.

This was my first idea, too. But then i found this entry in the
Changelog of the synaptics driver:

- In the DeviceOn() function, if opening the device node fails, try to
  auto-detect the correct event device again. This fixes some problems
  which occur after a suspend/resume cycle or after rmmod/insmod-ing
  the psmouse kernel driver.

I am not sure if this would help... According to the excerpt from X
log synaptics driver attempted to scan evdev devices and locate the
touchpad. However if this scan happen before udev had a chance to
process the event and create new /dev/input/eventX device node it will
fail.

Okay. This strengthens above statement. And udev is too slow to create
the devices, while the driver already scanned the directory.

I wonder if we should adjust the X driver to spin for a couple of
seconds in EventAutoDevProbe if the touchpad was already seen once...
Peter?