* 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20170523/57192830/attachment.html ^ 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 > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20170523/b9c5ddec/attachment-0001.html ^ 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 > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20170529/a48c35ca/attachment.html ^ 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 -- links below jump to the message on this page -- 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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