understanding of sysfs.

Greg KH greg at kroah.com
Tue May 23 05:23:17 EDT 2017

On Tue, May 23, 2017 at 12:58:07PM +0530, Madhu K wrote:
> Hi Greg,
> Thanks for your response.
> On Tue, May 23, 2017 at 12:04 PM, Greg KH <greg at kroah.com> wrote:
>     On Tue, May 23, 2017 at 11:58:31AM +0530, Madhu K wrote:
>     > Hi All,
>     >
>     > why there is no character device entry present in /sys/class? where as
>     block
>     > and net device entries are present.
>     I see character devices there, but not the device nodes.  I don't see
>     block device nodes there either.
> If I am wrong please correct me, there is a folder called block in /sys/class.
> is block not containing block device nodes? 

Nope, look closer :)

>     > Not only in /sys/class, for that matter why there is no character device
>     > entries present in /sys file system.
>     What do you exactly mean by "character device entries"?
> like block and net why there is no char folder  

Again, look closer please.

>     > please help me to understand for what purpose char devices are kept away
>     from /
>     > sys file system.
>     Have you read the driver model chapter in the Linux Device drivers book,
>     or the in-kernel sysfs documentation?

Again, please read all of the copious documentation that we have written
already about this topic.  If after that, you still have questions, I
will be more than glad to help answer them.


greg k-h

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