diff options
Diffstat (limited to 'Documentation/admin-guide/dynamic-debug-howto.rst')
| -rw-r--r-- | Documentation/admin-guide/dynamic-debug-howto.rst | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst index 8dc668cc1216..095a63892257 100644 --- a/Documentation/admin-guide/dynamic-debug-howto.rst +++ b/Documentation/admin-guide/dynamic-debug-howto.rst @@ -26,6 +26,11 @@ Dynamic debug provides: - format string - class name (as known/declared by each module) +NOTE: To actually get the debug-print output on the console, you may +need to adjust the kernel ``loglevel=``, or use ``ignore_loglevel``. +Read about these kernel parameters in +Documentation/admin-guide/kernel-parameters.rst. + Viewing Dynamic Debug Behaviour =============================== @@ -216,13 +221,15 @@ The flags are:: t Include thread ID, or <intr> m Include module name f Include the function name + s Include the source file name l Include line number + d Include call trace For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only the ``p`` flag has meaning, other flags are ignored. -Note the regexp ``^[-+=][flmpt_]+$`` matches a flags specification. -To clear all flags at once, use ``=_`` or ``-flmpt``. +Note the regexp ``^[-+=][fslmptd_]+$`` matches a flags specification. +To clear all flags at once, use ``=_`` or ``-fslmptd``. Debug messages during Boot Process @@ -258,7 +265,7 @@ Debug Messages at Module Initialization Time When ``modprobe foo`` is called, modprobe scans ``/proc/cmdline`` for ``foo.params``, strips ``foo.``, and passes them to the kernel along with -params given in modprobe args or ``/etc/modprob.d/*.conf`` files, +params given in modprobe args or ``/etc/modprobe.d/*.conf`` files, in the following order: 1. parameters given via ``/etc/modprobe.d/*.conf``:: @@ -320,13 +327,13 @@ Examples :#> ddcmd 'format "nfsd: READ" +p' // enable messages in files of which the paths include string "usb" - :#> ddcmd 'file *usb* +p' > /proc/dynamic_debug/control + :#> ddcmd 'file *usb* +p' // enable all messages - :#> ddcmd '+p' > /proc/dynamic_debug/control + :#> ddcmd '+p' // add module, function to all enabled messages - :#> ddcmd '+mf' > /proc/dynamic_debug/control + :#> ddcmd '+mf' // boot-args example, with newlines and comments for readability Kernel command line: ... |