On Mon, 3 Aug 2009, Mulyadi Santosa wrote: > On Mon, Aug 3, 2009 at 3:45 AM, Robert P. J. Day<rpjday@xxxxxxxxxxxxxx> wrote: > > > > i'm guessing there's no way to do this but, if you list the file > > /proc/devices, you see only the character and block devices and the > > major number corresponding to them: > > > > Character devices: > > 1 mem > > 4 /dev/vc/0 > > 4 tty > > 4 ttyS > > 5 /dev/tty > > 5 /dev/console > > 5 /dev/ptmx > > 7 vcs > > 10 misc > > 13 input > > 14 sound > > 21 sg > > 29 fb > > ... etc etc ... > > > > is there any way, from user space, to see the *minor* number region > > corresponding to those entries? > > How about "ls"? e.g: > > $ ls -li /dev/vcs* > 4472 crw-rw---- 1 vcsa tty 7, 0 2009-08-01 09:56 /dev/vcs > 8296 crw-rw---- 1 vcsa tty 7, 2 2009-08-01 09:56 /dev/vcs2 > > 7 is major number, 0 and 2 are minor number of vcs and vcs2 respectively... no, that shows you the subsequent *user space* device file creation results. to see what i mean, take a look at LDD3, http://lwn.net/Kernel/LDD3/, chapter 3. that chapter explains how a device driver can register its major and minor numbers with, say, alloc_chrdev_region(), but that operation does nothing about creating the appropriate the userspace /dev files -- that has to be done as a separate operation in userspace, and it's assumed you *know* what those minor numbers are. i'm asking if there's a way to see the results of that kernel space alloc_chrdev_region() call in terms of minor device numbers, information that is not provided in /proc/devices. rday -- ======================================================================== Robert P. J. Day Waterloo, Ontario, CANADA Linux Consulting, Training and Annoying Kernel Pedantry. Web page: http://crashcourse.ca Twitter: http://twitter.com/rpjday "Kernel Newbie Corner" column @ linux.com: http://cli.gs/WG6WYX ========================================================================
