Hi Greg, >> Dear Linux Team, >> >> I am trying to understand the USB Architecture and write my own client >> driver under Linux and some mew concepts of 2.6.x. > >What kind of "client driver"? Thanks for the response. Delayed as I was out these days. It is a USB based finger print authentication device. >> My point of about kref >> ---------------------- >> Used when the multiple threads are involved within the driver. >> I am not sure whether this can be when there are no thread within the >> driver and to control the Process synchronization. Can I get some >> clarity on this? > >Have you read the kref documentation that is in the kernel tree: > Documentation/kref.txt I am unsing 2.6.11.12. I found none. >That should explain how they should be used. > >> Main Question >> ------------- >> I have seen that kref_init () is issues in probe. // no issue with >> this >> >> Device memory allocation and Kref_get() call are issued in open context. >> Fine.ok. >> >> In that case kref_put should be called in close context or any error >> context. Right? >> Yes, I find these two being issued in the usb-skeleton driver. >> >> But, I find additional kref_put() call in disconnect? That too without >> any condition checking? Why do I need it here? > >Because the disconnect call to kref_put() matches the call to >kref_init() in probe. If you don't do this, you will leak memory. Thanks, that clear. So I guess, kref_put() will call the registered function when the refcount is '0'. >Also, have you read the Linux USB documentation? It's automatically >built for you when you run: > make psdocs >or > make pdfdocs >and will be in the Documentation/DocBook/usb.* file I will look at them. - Mukund Jampala -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
