From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lo.gmane.org (lo.gmane.org [80.91.229.12]) by yocto-www.yoctoproject.org (Postfix) with ESMTP id E331DE0126A for ; Sat, 3 Sep 2011 03:21:06 -0700 (PDT) Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1QznLU-0007dg-TM for poky@pokylinux.org; Sat, 03 Sep 2011 12:21:04 +0200 Received: from p578b5e99.dip0.t-ipconnect.de ([87.139.94.153]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 03 Sep 2011 12:21:04 +0200 Received: from gmane by p578b5e99.dip0.t-ipconnect.de with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 03 Sep 2011 12:21:04 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: poky@pokylinux.org From: Robert Berger Date: Sat, 03 Sep 2011 13:20:50 +0300 Organization: Reliable Embedded Systems Message-ID: References: <4E5D200B.20209@mlbassoc.com> Mime-Version: 1.0 X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: p578b5e99.dip0.t-ipconnect.de User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.20) Gecko/20110805 Thunderbird/3.1.12 In-Reply-To: <4E5D200B.20209@mlbassoc.com> Subject: Re: Debugging udev X-BeenThere: poky@yoctoproject.org X-Mailman-Version: 2.1.13 Precedence: list Reply-To: gmane@reliableembeddedsystems.com List-Id: Poky build system developer discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 03 Sep 2011 10:21:08 -0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Gary, I'm currently on the road and can not try it myself on a yocto/poky, so here are some wild guesses and ideas... On 08/30/2011 08:38 PM, Gary Thomas wrote: > I'm having trouble with udev creating all the devices I need in > my system. Based on the latest master, using udev 164. > > My system is based on the 3.0 kernel (mainline, not yocto) with > Video4Linux enabled with OMAP3 ISP. This creates a bunch of > special devices: > # ls /sys/class/video4linux/ > v4l-subdev0 v4l-subdev3 v4l-subdev6 video0 video3 video6 > v4l-subdev1 v4l-subdev4 v4l-subdev7 video1 video4 > v4l-subdev2 v4l-subdev5 v4l-subdev8 video2 video5 > However, udev is not actually creating the device nodes. > > Any ideas why? > Any hints on how to debug this? *) make sure udev is running - I guess it is. *) run on a terminal something like udevmonitor --env or udevadm monitor (don't know which one comes with poky) and load some kernel modules where udev works. Like this you should be able to see the messages sent by the kernel to udev. Manually load v4l so you can see if the kernel events are sent. *) if messages are sent, you most likely need to cook the udev config to create the proper devices for you *) Manually you could do make the /dev entries like this: If you run find /sys -name dev you will get many hits, such as: /sys/block/fd0/dev cat /sys/block/fd0/dev 2:0 means if loading this module, one should also create its device as follows: mknod /dev/fd0 b 2 0 Your goal should be to make a 'dev' entry appear under /sys for your device and then udev (and mdev in embedded busybox systems) will mknod it automatically. *) DEVTMPFS Besides I'm not a big fan of udev/mkdev for embedded systems since we have user space dependencies. The kernel obviously knows about the v4l class, but there are no device entries made. I prefer to use DEVTMPFS (enable CONFIG_DEVTMPFS in your kernel config) where the kernel makes the dev entries and you don't have user space dependencies. > > Thanks > I hope this gives you some new ideas;) Regards, Robert ..."Experience is what causes a person to make new mistakes instead of old ones." My public pgp key is available at: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x90320BF1