Official reference
The four values in printk denote: console_loglevel, default_message_loglevel, minimum_console_loglevel and default_console_loglevel respectively.
These values influence printk() behavior when printing or logging error messages. See ‘man 2 syslog’ for more info on the different loglevels.
- console_loglevel: messages with a higher priority than this will be printed to the console
- default_message_loglevel: messages without an explicit priority will be printed with this priority
- minimum_console_loglevel: minimum (highest) value to which console_loglevel can be set
- default_console_loglevel: default value for console_loglevel
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