Search

Technical Discussion Group Forum

This forum is provided for user discussion. While Beacon EmbeddedWorks support staff and engineers participate, Beacon EmbeddedWorks does not guarantee the accuracy of all information within in the Technical Discussion Group (TDG).

The "Articles" forums provide brief Articles written by Beacon EmbeddedWorks engineers that address the most frequently asked technical questions.

To receive email notifications when updates are posted for a Beacon EmbeddedWorks product download, please subscribe to the TDG Forum of interest.

TDG Forum

PrevPrev Go to previous topic
NextNext Go to next topic
Last Post 08 Apr 2005 09:04 AM by  tozyagcilar
/dev/pwm0 error, LCD-6.4-VGA-10
 5 Replies
Sort:
You are not authorized to post a reply.
Author Messages
simon
New Member
New Member
Posts:


--
25 Jul 2004 08:11 PM
    Hi guys,

    I've got a LH79520-10 SDK and the LCD-6.4-VGA-10 Display Kit. I've followed the directions given by the pdf's and am also using the patches as suggested by JadePheonix.

    I have also changed the kernel-config file to indicate that my display is the 6.4" by doing this:
    # CONFIG_PL110_LQ39=y - original setting
    CONFIG_PL110_LQ64=y


    I've added in a file /etc/pointercal as i was getting an error trying to open it.

    I can tftp and nfs root with no probs, though i do get a modprobe: modprobe: Can't locate module char-major-4

    BUT after booting, I am getting the following error:
    modprobe: modprobe: Can't locate module char-major-254
    open(/dev/pwm0) error


    I can happily log in as root via minicom and do command line stuff, but the LCD/touchscreen is not happy, it has grey/colour lines strobing vertically.

    I've run the "video-open" tools from losh and it does all work.

    Any ideas/clues etc?

    Cheers,
    Simon
    JadePhoenix
    New Member
    New Member
    Posts:


    --
    26 Jul 2004 05:13 AM
    Hello!

    Quote:
    modprobe: Can't locate module char-major-4


    /usr/src/linux/Documentation/devices.txt

    When trying to load module for 'char-major-4', the corresponding line from "modules.conf" is going to be read.
    "modules.conf" isnt there by default.
    Normally it defines an alias to "serial" device (serial.o).

    Using the Embedix BDK kernel, the serial port stuff is already compiled in, no need to dynamically load.
    If you create a file

    Quote:

    /etc/modules.conf


    and place a line like

    Quote:

    alias char-major-4 off


    The error should be gone - though another message appears now

    Quote:

    modprobe: Note: /etc/modules.conf is more recent than /lib/modules/2.4.17-rmk2-l
    ineo5/modules.dep


    Which isnt harmful i think (because the referred file is empty).

    Regards
    JadePhoenix
    New Member
    New Member
    Posts:


    --
    26 Jul 2004 05:19 AM
    Oh well .. for the other error...

    The 254 seems to be a dynamically allocated major number.
    I guess one has to add some alias (like char-major-4 one) to "modules.conf".
    Like:

    Quote:

    alias char-major-254 some_driver


    Make sure /dev/pwm0 exists and can be opened.

    Regards
    simon
    New Member
    New Member
    Posts:


    --
    26 Jul 2004 06:59 PM
    Hi JadePheonix,

    I added in the modules.conf as you suggested and recompiled the kernel after I did a make config and selected the correct display. The display is working now, but I am still getting the /dev/pwm0 error and module-char-254 error. The /dev/pwm0 does exist and is readable. I'm now stuck in trying to get QT to get out of the touchscreen calibration loop.

    Cheers,
    Simon
    JadePhoenix
    New Member
    New Member
    Posts:


    --
    27 Jul 2004 09:43 AM
    Hello,

    well i have no experience at all with that touch screen stuff ... i googled a bit around an found following site with some code fragments:

    http://wearcam.org/eyetap_focus_controller/

    http://wearcam.org/ece385...r_code_fragments.htm

    and some sample program:

    http://wearcam.org/ece385...ver_only_one_servo.c

    Maybe you can use instructions and sample code collected there to verify some stuff.

    Regards
    tozyagcilar
    New Member
    New Member
    Posts:


    --
    08 Apr 2005 09:04 AM
    Hey Simon,

    Did you manage to fix this problem. I am getting the same errors. Please post your solution if you find one.
    You are not authorized to post a reply.