* understanding of sysfs.
@ 2017-05-23 6:28 Madhu K
2017-05-23 6:34 ` Greg KH
0 siblings, 1 reply; 6+ messages in thread
From: Madhu K @ 2017-05-23 6:28 UTC (permalink / raw)
To: kernelnewbies
Hi All,
why there is no character device entry present in /sys/class? where as
block and net device entries are present.
Not only in /sys/class, for that matter why there is no character device
entries present in /sys file system.
please help me to understand for what purpose char devices are kept away
from /sys file system.
Thanks
Madhu
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^ permalink raw reply [flat|nested] 6+ messages in thread
* understanding of sysfs.
2017-05-23 6:28 understanding of sysfs Madhu K
@ 2017-05-23 6:34 ` Greg KH
2017-05-23 7:28 ` Madhu K
0 siblings, 1 reply; 6+ messages in thread
From: Greg KH @ 2017-05-23 6:34 UTC (permalink / raw)
To: kernelnewbies
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.
> 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"?
> 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?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* understanding of sysfs.
2017-05-23 6:34 ` Greg KH
@ 2017-05-23 7:28 ` Madhu K
2017-05-23 9:23 ` Greg KH
0 siblings, 1 reply; 6+ messages in thread
From: Madhu K @ 2017-05-23 7:28 UTC (permalink / raw)
To: kernelnewbies
Hi Greg,
Thanks for your response.
On Tue, May 23, 2017 at 12:04 PM, Greg KH <greg@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?
>
>
> > 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
>
> > 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?
>
> thanks,
>
> greg k-h
>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* understanding of sysfs.
2017-05-23 7:28 ` Madhu K
@ 2017-05-23 9:23 ` Greg KH
2017-05-29 5:28 ` Madhu K
0 siblings, 1 reply; 6+ messages in thread
From: Greg KH @ 2017-05-23 9:23 UTC (permalink / raw)
To: kernelnewbies
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@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.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* understanding of sysfs.
2017-05-23 9:23 ` Greg KH
@ 2017-05-29 5:28 ` Madhu K
2017-05-29 5:43 ` Greg KH
0 siblings, 1 reply; 6+ messages in thread
From: Madhu K @ 2017-05-29 5:28 UTC (permalink / raw)
To: kernelnewbies
On Tue, May 23, 2017 at 2:53 PM, Greg KH <greg@kroah.com> wrote:
> 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@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 :)
>
I checked the block folder, the entries which are present in
/sys/class/block are softlink to /sys/devices nodes. what i understand from
this is, all block net and char node entries are present in /sys/devices.
Am i correct?
>
> > > 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.
>
> thanks,
>
> greg k-h
>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* understanding of sysfs.
2017-05-29 5:28 ` Madhu K
@ 2017-05-29 5:43 ` Greg KH
0 siblings, 0 replies; 6+ messages in thread
From: Greg KH @ 2017-05-29 5:43 UTC (permalink / raw)
To: kernelnewbies
On Mon, May 29, 2017 at 10:58:09AM +0530, Madhu K wrote:
>
>
> On Tue, May 23, 2017 at 2:53 PM, Greg KH <greg@kroah.com> wrote:
>
> 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@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 :)
>
>
> I checked the block folder, the entries which are present in /sys/class/block
> are softlink to /sys/devices nodes.
What do you exactly mean by "nodes"? /sys/class/block/ points to the
block device "class devices" in the kernel device hierarchy, just like
the other /sys/class/* entries point to other class devices.
> what i understand from this is, all block net and char node entries
> are present in /sys/devices. Am i correct?
Again, what do you mean by a "node"? Did you read the documentation
about sysfs and the driver model?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-05-29 5:43 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2017-05-23 6:28 understanding of sysfs Madhu K
2017-05-23 6:34 ` Greg KH
2017-05-23 7:28 ` Madhu K
2017-05-23 9:23 ` Greg KH
2017-05-29 5:28 ` Madhu K
2017-05-29 5:43 ` Greg KH
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