AllowEmptyInput and HAL

Phil Endecott spam_from_xorg at
Wed Apr 29 11:32:14 PDT 2009

Daniel Stone wrote:
> Hi,
> On Tue, Apr 28, 2009 at 10:01:25PM +0100, Phil Endecott wrote:
>> Specifically, when X started I had no keyboard or mouse.   After 
>> power-cycling [no other way to escape!] I found a message in the log 
>> saying that "AllowEmptyInput" was enabled and that my keyboard and 
>> mouse configuration was being ignored.  Having looked this up in man 
>> xorg.conf I see that this mode is the default.  I'll try to be polite: 
>> This does not seem like the most useful behaviour.
> AllowEmptyInput does not mean that your keyboard and mouse configuration
> is being ignored; conversely, it means that it's not a fatal error to
> have no keyboard and mouse configuration whatsoever.  So if AEI changes
> anything, you don't have a keyboard and mouse configured.

Here is what it reported in the log:

(WW) AllowEmptyInput is on, devices usingdrivers 'kbd, 'mouse' or 
'vmmouse' will be disabled.
(WW) Disabling Generic Keyboard
(WW) Disabling Evoluent Vertical Mouse

That looks to me as if the default setting of that option causes X to 
ignore (or "disable", if that means something different) my keyboard 
and mouse.

>> Having set AutoAddDevices to false in order to disable the unhelpful 
>> AllowEmptyInput, I now have a functioning mouse.  But I have a keyboard 
>> where every alternate keystroke produces the right letter and the 
>> others produce garbage (maybe top-bit-set characters?).
> Cool.  Could you please send xev output?

Unfortunately this is hard as I cannot log in.  Presumably there is 
some way in which I can bypass xdm and cause X to start running and 
then start xev from another machine, or something.  I'll investigate.

Looking at this some more, here is what I think is happening.  This is 
based on what I type at the xdm username: prompt.  Characters are 
alternately normal and sent with Ctrl.  So e.g. h is backspace, j shows 
a glyph with a V above a T for vertical tab, etc.  I also get 
box-drawing characters for some letters.

>> I also noticed some messages in the log where "config/hal" complained 
>> that "NewInputDeviceRequest failed".  Presumably this is because of my 
>> AutoAddDevices.  I had noticed that Debian installed "hal"; I had not 
>> previously heard of it.  It looks like something that sits on top of udev.
> Yes, it is.  NewInputDeviceRequest failing sounds like the evdev driver
> isn't installed.

evdev was listed in the Modules section (I had been using it previously 
for the Powermate) and I don't recall any problems with it mentioned in 
the log.

> BTW, attaching complete logs instead of two-word
> snippets often leads to significantly more happiness.

I would love to copy-and-paste the logs but I am sending this from 
another computer.  The bit above was re-typed.

>> So I've now spent most of three days on this.  I just want a computer 
>> that works, preferably as well as the old one did, and while I don't 
>> have one I can't do much work [I'm self-employed].  So could someone 
>> please suggest what I should do:
>> - Is there some simple set of xorg.conf settings that will make it just 
>> work like it did before, without any AllowEmptyInput and HAL stuff and 
>> with a functional keyboard?
> The Debian guys can explain that much better than me.
>> - Or would I be better off trying to learn how this HAL thing works?
>> X is something that I only have to understand once every few years when 
>> I have some new hardware.  By the next time I need to understand it, 
>> either I have forgotten something vital or it has all changed....
> Well, not upgrading guarantees there won't be any changes. :)

I would have loved to not upgrade.  There was nothing wrong with the 
old system until it broke.

Paul Menzel suggests that I should be able to run with no Xorg.conf.  
When I try this I still get the bizarre keyboard behaviour.

The Debian package versions are:

xserver-xorg 7.4+1
xserver-xorg-core 1.6.1-1
xserver-xorg-input-evdev 2.2.1-1
xserver-xorg-input-kbd 1.3.2-3
xserver-input-mouse 1.4.0-2
xserver-xorg-input-synaptics 1.1.0-1
xserver-xorg-video-openchrome 0.2.903+svn741-1+b1

Regards,  Phil.

More information about the xorg mailing list