[yocto] adding a udev entry for a camera

Gary Thomas gary at mlbassoc.com
Thu Oct 31 08:55:33 PDT 2013 

On 2013-10-31 09:45, Edward Vidal wrote:
> Hello all,
> less /etc/udev/rules.d/10-c920.rules
> WARNING: terminal is not fully functional
> SUBSYSTEM=="video4linux", BUS=="usb", ATTRS{idvendor}=="0x046d", ATTRS{idProduct
> }=="0x082d", NAME="video0", MODE:="0660"
> It appears the key BUS is not correct based on the tests below.
> My mknod is /bin/mknod.
> find / -name sysfs
> /usr/include/sysfs
> /usr/src/kernel/fs/sysfs

Note: chasing this udev behaviour is a waste of time if the kernel doesn't recognize
and support your device.

Have you even looked to see if this camera is supported in your kernel?  I could
not find a driver for it when I looked, even in the latest mainline kernel.

What kernel are you trying to use?

>
> udevadm test --action=add /usr/include/sysfs or udevadm test --action=add /usr/src/kernel/fs/sysfs unable to open device '/sys/usr/src/kernel/fs/sysfs'
> run_command: calling: test
> adm_test: version 182
> This program is for debugging only, it does not run any program,
> specified by a RUN key. It may show incorrect results, because
> some values may be different, or not available at a simulation run.
>
> builtin_kmod_init: load module index
> add_matching_files: unable to open '/var/run/udev/rules.d': No such file or directory
> parse_file: reading '/etc/udev/rules.d/10-c920.rules' as rules file
> add_rule: unknown key 'BUS' in /etc/udev/rules.d/10-c920.rules:1
> add_rule: invalid rule '/etc/udev/rules.d/10-c920.rules:1'
>
> lots of output
>
> udev_rules_new: rules use 18408 bytes tokens (1534 * 12 bytes), 12756 bytes buffer
> udev_rules_new: temporary index used 12800 bytes (640 * 20 bytes)
> unable to open device '/sys/usr/include/sysfs'
> builtin_kmod_exit: unload module index
>
> Do I add RUN+="/bin/mknod /dev/video0 c 81 0" see below new version of 1--c920.rules
> cat 10-c920.rules
> SUBSYSTEM=="video4linux", BUS=="usb", ATTRS{idvendor}=="0x046d", ATTRS{idProduct}=="0x082d", NAME="video0", MODE:="0660", RUN+="/bin/mknod /dev/video0 c 81 0"
> udevadm test --action=add /usr/src/kernel/fs/sysfs
> run_command: calling: test
> adm_test: version 182
> This program is for debugging only, it does not run any program,
> specified by a RUN key. It may show incorrect results, because
> some values may be different, or not available at a simulation run.
>
> builtin_kmod_init: load module index
> add_matching_files: unable to open '/var/run/udev/rules.d': No such file or directory
> parse_file: reading '/etc/udev/rules.d/10-c920.rules' as rules file
> add_rule: unknown key 'BUS' in /etc/udev/rules.d/10-c920.rules:1
> add_rule: invalid rule '/etc/udev/rules.d/10-c920.rules:1'
>
> Where do you find information for working with rules other than just some examples?
>
> Thanks
>
>
> On Thu, Oct 31, 2013 at 8:41 AM, Khem Raj <raj.khem at gmail.com <mailto:raj.khem at gmail.com>> wrote:
>
>     On Wed, Oct 30, 2013 at 6:12 PM, Edward Vidal <vidal.develone at gmail.com <mailto:vidal.develone at gmail.com>> wrote:
>     > Hello,
>     > This is when I connect the camera
>     > udevadm monitor test
>     > monitor will print the received events for:
>     > UDEV - the event which udev sends out after rule processing
>     > KERNEL - the kernel uevent
>     >
>     > KERNEL[803.263336] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4 (usb)
>     > KERNEL[803.267456] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.0
>     > (usb)
>     > KERNEL[803.269287] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.1
>     > (usb)
>     > KERNEL[803.269958] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.2
>     > (usb)
>     > KERNEL[803.270721] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.3
>     > (usb)
>     > KERNEL[803.276214] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/usb_device/usbdev1.15
>     > (usb_device)**********
>     > UDEV  [803.277191] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4 (usb)
>     > UDEV  [803.306091] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/usb_device/usbdev1.15
>     > (usb_device)
>     > UDEV  [803.318603] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.2
>     > (usb)
>     > UDEV  [803.324249] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.1
>     > (usb)
>     > UDEV  [803.329712] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.0
>     > (usb)
>     > UDEV  [803.333160] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.3
>     > (usb)
>     >
>     > still no /dev/video0
>     > ls -la /dev/v*
>     > crw-rw---- 1 root tty 7,   0 Jan  1  2000 /dev/vcs
>     > crw-rw---- 1 root tty 7,   1 Jan  1  2000 /dev/vcs1
>     > crw-rw---- 1 root tty 7,   2 Jan  1  2000 /dev/vcs2
>     > crw-rw---- 1 root tty 7,   3 Oct 29 13:51 /dev/vcs3
>     > crw-rw---- 1 root tty 7, 128 Jan  1  2000 /dev/vcsa
>     > crw-rw---- 1 root tty 7, 129 Jan  1  2000 /dev/vcsa1
>     > crw-rw---- 1 root tty 7, 130 Jan  1  2000 /dev/vcsa2
>     > crw-rw---- 1 root tty 7, 131 Oct 29 13:51 /dev/vcsa3
>     > root at beagleboard:~# lsusb
>     > Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
>     > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>     > Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>     > Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
>     > Bus 001 Device 004: ID 0409:0059 NEC Corp. HighSpeed Hub
>     > Bus 001 Device 005: ID 413c:2005 Dell Computer Corp. RT7D50 Keyboard
>     > Bus 001 Device 006: ID 046d:c001 Logitech, Inc. N48/M-BB48 [FirstMouse Plus]
>     > Bus 001 Device 015: ID 046d:082d Logitech, Inc.
>     > ***********************************************************************************
>     >
>     >
>     > udevadm monitor --udev
>     > monitor will print the received events for:
>     > UDEV - the event which udev sends out after rule processing
>     > camera removed*****************************************************
>     > UDEV  [1325.916811] remove
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.1
>     > (usb)
>     > UDEV  [1325.918489] remove
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.0
>     > (usb)
>     > UDEV  [1325.919282] remove
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.2
>     > (usb)
>     > UDEV  [1325.923005] remove
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.3
>     > (usb)
>     > UDEV  [1325.928437] remove
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/usb_device/usbdev1.15
>     > (usb_device)
>     > UDEV  [1325.932709] remove
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4 (usb)
>     > camera added
>     > ***************************************************************************
>     > UDEV  [1329.344727] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4 (usb)
>     > UDEV  [1329.376313] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/usb_device/usbdev1.16
>     > (usb_device)
>     > UDEV  [1329.389008] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.2
>     > (usb)
>     > UDEV  [1329.396241] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.1
>     > (usb)
>     > UDEV  [1329.401795] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.0
>     > (usb)
>     > UDEV  [1329.406739] add
>     > /devices/platform/usbhs_omap/ehci-omap.0/usb1/1-2/1-2.3/1-2.3.4/1-2.3.4:1.3
>     > (usb)
>     >
>     > This is what I get in /var/log/messages
>     > Oct 29 14:17:28 beagleboarduser.info <http://user.info> kernel: usb 1-2.3.4: USB disconnect,
>     > device number 16
>     > Oct 29 14:17:31 beagleboarduser.info <http://user.info> kernel: usb 1-2.3.4: new high-speed
>     > USB device number 17 using ehci-omap
>     > Is there anything else that I can test  / provide
>
>     OK another thing to try is
>
>     udevadm test --action=add /sys/....
>
>     where /sys/... is path to your device in sysfs
>
>     this should give enough reason to what udev is doing when its getting an add
>     event for this device.
>
>     Secondly in your udev rule refer mknod with absolute path like
>     /sbin/mknod or /bin/mknod where ever it is
>
>
>
>
> _______________________________________________
> yocto mailing list
> yocto at yoctoproject.org
> https://lists.yoctoproject.org/listinfo/yocto
>

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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