/proc/bus/input/devices changing while booting

/proc/bus/input/devices changing while booting

[Stefan Sassenberg]

Hello,

while booting, an init-script on my machine greps the Handlers entry of 
a certain device (USB touchscreen) from /proc/bus/input/devices. It ends 
with "event2", so I configure my software to listen for events in 
/dev/input/event2. A few seconds later /proc/bus/input/devices changes, 
the order of the devices is different and the Handlers entry for my 
device ends with event1 making my device misconfigured and thus unusable.

Can anybody explain that behaviour? How can I get the final eventX 
device file?

I'm using kernel 2.6.28.8 on an Intel Celeron, chipset ICH5.

Regards

Stefan

Re: /proc/bus/input/devices changing while booting

[Dmitry Torokhov]

Hi Stefan,

On Wed, Mar 25, 2009 at 05:20:56PM +0100, Stefan Sassenberg wrote:
> Hello,
>
> while booting, an init-script on my machine greps the Handlers entry of  
> a certain device (USB touchscreen) from /proc/bus/input/devices. It ends  
> with "event2", so I configure my software to listen for events in  
> /dev/input/event2. A few seconds later /proc/bus/input/devices changes,  
> the order of the devices is different and the Handlers entry for my  
> device ends with event1 making my device misconfigured and thus unusable.
>
> Can anybody explain that behaviour? How can I get the final eventX  
> device file?
>
> I'm using kernel 2.6.28.8 on an Intel Celeron, chipset ICH5.
>

Something causes disconnect of your touchscreen. I think this can happen of 
EHCI is loaded after UHCI/OHCI and they all figure our which devices should be 
driven by whom. Does it help if you compile EHCI in kernel or make sure it 
gets loaded first?

-- 
Dmitry