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Old 03-24-2007, 01:15 PM   #1
Sergei Lavrov
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printk(KERN_DEBUG ...) vs printk(...)

What is difference between printk(KERN_DEBUG ...) and printk( ...) ?
After I replace the latter with the former, the kernel is not dumping debug messages anymore.
Old 03-25-2007, 05:00 PM   #2
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Well, I know nothing about Kernel editing so I'll take a stab at it.

The KERN_DEBUG is telling printk to print only anything related to KERN_DEBUG whereas printk with no arguments will print everything.
Old 03-25-2007, 05:41 PM   #3
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From "Linux Device Drivers" by Corbet et al, page 77:
A printk statement with no specified priority defaults to DEFAULT_MESSAGE_LOGLEVEL, specified in kernel/printk.c as an integer. In the 2.6.10 kernel, DEFAULT_MESSAGE_LOGLEVEL is KERN_WARNING, but that has been known to change in the past.
There's more. Buy the book.


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