sysmo-bts
/
generic-poky
9
0
Fork 0
Code Pull Requests Releases Activity

udev: update local rules for new touchscreen device 

* While working with a new capacitive touchscreen it was found
  that the existing udev rule that creates the
  /dev/input/touchscreen0 symlink was too restrictive and did not
  match the MODALAIS entry for this touchscreen. which is:

  MODALIAS=input:b0018v0000p0000e0000-e0,1,3,k14A,ra0,1,2F,35,36,39,mlsfw

* By looking at the input_print_modalias function in the Linux
  kernel drivers/input/input.c file and referencing the meaning
  of the evbits and attributes of the input_dev structure it seems
  that for identification of a touchscreen the match with ,18
  which was matching part of the absbit structure is overkill.

* It seems that the absbit entry is used for devices like
  touchscreens and if that the the "a" is followed by 0 and 1 this
  is sufficient.

* So the logic has now been changed to check for the "e" 0 and 3
  values which correspond to EV_SYN and EV_ABS, then check for
  the "a" attribute with 0 and 1.

* More information and history for this can be found at:
    http://patchwork.openembedded.org/patch/25093/
    http://thread.gmane.org/gmane.comp.handhelds.openembedded.core

* This patch mirrors a patch done by:
    Andrea Adami <andrea.adami@gmail.com>

(From OE-Core rev: d95a9b516861594bc89c7ee8079bab2904703ad2)

Signed-off-by: Chase Maupin <Chase.Maupin@ti.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Chase Maupin 2013-10-14 15:20:01 -05:00 committed by Richard Purdie
parent 9d8fc0268e
commit 75b0fb2ab9
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
meta/recipes-core/udev/udev/local.rules
View File

@ -17,5 +17,7 @@
ACTION=="add", DEVPATH=="/devices/*", ENV{MODALIAS}=="?*", RUN+="/sbin/modprobe $env{MODALIAS}"
# Create a symlink to any touchscreen input device
SUBSYSTEM=="input", KERNEL=="event[0-9]*", ATTRS{modalias}=="input:*-e0*,3,*a0,1,*18,*", SYMLINK+="input/touchscreen0"
# Trigger based on input type, that the evbit (-e) has EV_SYN and EV_ABS,
# has an EV_ABS value (-a) which is used for touchscreen type devices.
SUBSYSTEM=="input", KERNEL=="event[0-9]*", ATTRS{modalias}=="input:*-e0*,3,*a0,1,*", SYMLINK+="input/touchscreen0"