Thank you so much, Thibaut. I have spotted the source-code logic in include/linux/prink.h
Cheers, Wenda Ni, Ph.D. On Mon, Oct 17, 2016 at 7:41 PM, Thibaut SAUTEREAU < [email protected]> wrote: > On Mon, Oct 17, 2016 at 07:17:32PM -0400, Wenda Ni wrote: >> Dear all, >> >> I am working on a kernel module that incorporate both pr_debug and >> pr_warn. I would like to see pr_debug messages from dmesg. >> >> What I followed is to specify kernel parameter by saying "loglevel=7". >> This can be seen confirmed from /proc/cmdline. But still, I donot get >> pr_debug level messages either from dmesg or from /var/log/messages. I >> also tried echo 7 > /proc/sys/kernel/printk. It does not return what I >> expect, either. >> >> Let me know what I am missing. Thank you very much in advance. >> >> Cheers, >> >> Wenda Ni, Ph.D. >> >> _______________________________________________ >> Kernelnewbies mailing list >> [email protected] >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > Hello Wenda, > > I encountered the same issue a while ago. > As stated here: http://elinux.org/Debugging_by_printing > pr_debug is replaced with an empty statement unless the kernel is compiled > with DEBUG. So if you just want to play with printing kernel debug logs, > just define the DEBUG macro in your module source file for testing. > > I also observed that without a new line character at the end of the string > passed to pr_debug, I could not find the log line in dmesg output. Not sure > where this comes from. > > -- > Thibaut SAUTEREAU
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