From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Sun, 24 Feb 2013 18:26:20 +0100 Subject: [Buildroot] editing device_table_dev.txt In-Reply-To: <5126AC9B.30302@mind.be> References: <1361403460.22521.44.camel@genx.eng.msli.com> <5125F38B.2030204@petroprogram.com> <5125F50C.7020902@petroprogram.com> <20130221102315.GB12155@sapphire.tkos.co.il> <5125F7BB.50403@petroprogram.com> <5126A675.2060308@mind.be> <5126A8C7.2000009@petroprogram.com> <5126AC9B.30302@mind.be> Message-ID: <20130224182620.2283ceb3@skate> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Dear Arnout Vandecappelle, On Fri, 22 Feb 2013 00:24:11 +0100, Arnout Vandecappelle wrote: > > What you mean that mdev or udev does not create device nodes ??? > > If older kernels don't support devtmpfs like Baruch > > said then who does that device node creation if not the mdev or udev > > when event happens ??? > > Well, nobody... > > Turns out that mdev still does device node creation. Makes me > wonder if I'm not mistaken about udev as well... I just remember > hearing that device node creation was removed when DEVTMPFS was > introduced. Yes, I think you got the thing wrong: udev and mdev are still creating the device nodes. Of course, they might have already been created by devtmpfs, but I don't think it is a requirement. At least, devtmpfs is definitely not a requirement for mdev to work (except in Buildroot, in which we made the decision that if mdev is to be used, then devtmpfs support must be there). > >> That said, you can create custom mdev/udev rules to create device > >> nodes. But it's all manual - and much simpler to just create the > >> device nodes manually. > >> > > > > for mdev it's just a single file, /etc/mdev.conf (I can even > > copy-paste it here, it's not that long and will cover 99% of needs). > > Yes, but that file just specifies the chmod/chown rules, not how to > create the device nodes. But as I just saw in the code, mdev does in > fact create the device nodes. udev can also create symbolic links to device files based on custom rules, or other funky things. Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com