On Wed, Apr 16, 2014 at 2:46 PM, Martin Kepplinger <martink@posteo.de> wrote: > Am 2014-04-16 11:00, schrieb Arun KS: >> Hi Martin,
>> >> On Wed, Apr 16, 2014 at 2:13 PM, Martin Kepplinger <martink@posteo.de> wrote: >>> I'm on Debian here and I don't really get pr_debug and printk(KERN_DEBUG
>>> ...). Let's stick to pr_debug. >>> >>> I have DYNAMIC_DEBUG enabled and >>> root@laptop:/proc/sys/kernel# cat /proc/sys/kernel/printk >>> 7 7 1 7
>> This shows the console log level. >> This file controls the traffic to console. But all the log messages >> will be present in logbuf. > > How do I view debug messages from logbuf?
> >> >>> >>> I write a module with pr_debug's. I load the module and I *don't* see >>> anything in /var/log/messages (or anywhere in /var/log/* ). Adding >>> #define DEBUG doesn't help.
>>> >>> /sys/kernel/debug/dynamic_debug/control has the pr_debug entries I use >>> in my loaded module. >>> >>> In short: How do I see debug log messages? Using pr_info() works as
>>> expected. What am I missing? Do I need to edit my Makefile? >> Did you enable dynamic printing for your file? >> >> Below command enables dynamic printing for file sdhci.c. >> echo 'file sdhci.c +p' > /sys/kernel/debug/dynamic_debug/control
> > well. I tried that. The thing is, the pr_debug() symbols are in > "control" only after "insmod my_module". Then I can echo -n 'file > my_mobule.c +p' > control > But my pr_debug() messages get printed directly after insmod, basically
> in my module_init function. Enabling my file doesn't output anything in > /var/log/* So now you know why your pr_debug is absent in logbuf.
You can make your module as a built in and use bootargs.