Accelerometer problem

Timo Drick timo at
Sat Jul 12 16:15:59 CEST 2008

Andy Green schrieb:
> Hash: SHA1
> Somebody in the thread at some point said:
> | On the OM2007.2 images it is the neod which opens the 
> accelerometers. No
> | reason for doing so, even more as neod starts to eat 50% CPU, because
> | the am's send both 100 events per second...
> |
> | If anybody is interested, I recompiled the neod without this and 
> without
> | the click-sound. Drop me a mail.
> |
> | No more probs with the am's and everything a lot faster.
> Well I am glad to hear it can be made stable, because I did believe I
> fixed the instability last patch set.
> However I don't get why neod sucking on the input device too makes
> trouble (other than the CPU load or whatever).  The input layer in Linux
> takes care about copying the input content around consistently so
> everyone with the input device open gets one copy of what's happening.
> Ie, the accel driver is not aware that there are multiple apps
> listening.  I guess it is a bug in the accel driver somehow still, but a
> much less worrying one that the SPI sharing difficulties until now.
> - -Andy

Hi Andy,

if i shutdown X-Server i am able to open the /dev/input/events twice or 
more times. And it work. So it should be not the problem if the device 
is opened by multiple processes. Just if the X-Server is up only one 
event work. lsof show that all events are opened by neod:
neod      1675          root    4r   CHR      13,64               1427 
neod      1675          root    6r   CHR      13,65               1568 
neod      1675          root    7r   CHR      13,66               1590 
neod      1675          root    8r   CHR      13,67               1609 
neod      1675          root    9r   CHR      13,68               1464 

-- Timo

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