[meta-intel] [PATCH] formfactor: detect USB HID keyboard and touch screen

[Jianxun Zhang]

> On Jun 8, 2016, at 2:06 PM, Tom Zanussi <tom.zanussi at linux.intel.com> wrote:
> 
> Hi Jianxun,
> 
> On 06/07/2016 06:46 PM, Jianxun Zhang wrote:
>> The new machconfig probes USB keyboard and touch screen, and
>> then sets HAVE_* variables according to detection.
>> 
>> Detectable devices:
>> USB HID keyboards (Generic Desktop)
>> USB HID touch screens (Digitizer)
>> 
>> Note:
>> The intention is to have a way to provide initial formfactor
>> settings in a boot procedure. That means supported keyboard
>> and touch screen must be connected before machconfig runs.
>> Any new connection or disconnection won't be detected until
>> machconfig is executed again.
>> 
>> Limitation:
>> There could be some USB HID devices presents more than one
>> usage in a single descriptor. We will add support once such
>> device emerges.
>> 
>> Some platforms may have _virtual_ devices provided by BIOS.
>> It will cause false detection when they are presented as
>> types we supported. We can add black list logic when it
>> becomes a big concern.
>> 
>> Fixes [YOCTO #9205]
>> 
>> Signed-off-by: Jianxun Zhang <jianxun.zhang at linux.intel.com>
>> ---
>> .../recipes-bsp/formfactor/formfactor/machconfig   | 37 ++++++++++++++++++++++
>> .../recipes-bsp/formfactor/formfactor_0.0.bbappend |  1 +
>> 2 files changed, 38 insertions(+)
>> create mode 100644 common/recipes-bsp/formfactor/formfactor/machconfig
>> create mode 100644 common/recipes-bsp/formfactor/formfactor_0.0.bbappend
>> 
>> diff --git a/common/recipes-bsp/formfactor/formfactor/machconfig b/common/recipes-bsp/formfactor/formfactor/machconfig
>> new file mode 100644
>> index 0000000..17d4978
>> --- /dev/null
>> +++ b/common/recipes-bsp/formfactor/formfactor/machconfig
>> @@ -0,0 +1,37 @@
>> +# Note: super user permission is required to run usbhid-dump
>> +# successfully.
>> +
>> +# HEX keys are according to USB HID spec and USB HID usage table
>> +# We could add more keys as needed in the future.
>> +
>> +# checker for generic USB HID keyboard
>> +USBHID_KBD_CMD="grep -E '^ 05 01 09 06'"
>> +
>> +# checker for touch screen
>> +USBHID_TS_CMD="grep -E '^ 05 0D 09 04'"
>> +
>> +# It may not be very accurate. Here we only look for first two lines
>> +# of a descriptor section. Example:
>> +#
>> +# 001:003:000:DESCRIPTOR         1460501386.337809
>> +#  05 01 09 02 A1 01 09 01 A1 00 05 09 19 01 29 03
>> +#  15 00 25 01 95 03 75 01 81 02 .. .. .. .. .. ..
>> +#  .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
>> +#
>> +# By doing so we elimiate false matches when HEX keys are in the lines
>> +# in the middle of whole descriptor section.
>> +
>> +USBHID_DUMP_OUTPUT=$(usbhid-dump -e descriptor|grep -A1 DESCRIPTOR)
>> +
>> +if echo "$USBHID_DUMP_OUTPUT"|eval $USBHID_TS_CMD &>/dev/null; then
>> +    HAVE_TOUCHSCREEN=1
>> +fi
>> +
>> +if echo "$USBHID_DUMP_OUTPUT"|eval $USBHID_KBD_CMD &>/dev/null; then
>> +    HAVE_KEYBOARD=1
>> +else
>> +    # config script in OE will set HAVE_KEYBOARD=1
>> +    # if we don't set any value. We have to explicitly
>> +    # tell it when keyboard is not detected.
>> +    HAVE_KEYBOARD=0
>> +fi
> 
> What if usbhid-dump doesn't exist?  In that case, not detecting a
> keyboard doesn't mean there isn't one.
> 
> I think Saul suggested you check for usbhid-dump first and then exit
> having touched nothing that would deviate from the defaults.
oops, I had another talk with Saul about default value set in config. My previous comment is an answer for that totally different question :-(
Yes, I agree with this and actually think the new detection should be skipped when any errors are tossed by the command, including the case cmd doesn’t exist.

Put that line "USBHID_DUMP_OUTPUT=$(usbhid-du...” in an if statement should resolve such problems. I will submit another V3 with some tests

Thanks lot!

> 
> Tom
> 
>> diff --git a/common/recipes-bsp/formfactor/formfactor_0.0.bbappend b/common/recipes-bsp/formfactor/formfactor_0.0.bbappend
>> new file mode 100644
>> index 0000000..72d991c
>> --- /dev/null
>> +++ b/common/recipes-bsp/formfactor/formfactor_0.0.bbappend
>> @@ -0,0 +1 @@
>> +FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
>> 
>