path: root/Documentation/dynamic-debug-howto.txt
diff options
authorVladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>2012-12-05 16:48:27 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-17 12:19:09 -0800
commit7a555613eb77c69eb6e48b61bc5f72dd42fa1780 (patch)
treefd2c5ef59a77ba532a5957923f9919fa170027f9 /Documentation/dynamic-debug-howto.txt
parentf657fd21e16e3ab7432c03008e19069c2ef8e150 (diff)
dynamic_debug: dynamic hex dump
Introduce print_hex_dump_debug() that can be dynamically controlled, similar to pr_debug. Also, make print_hex_dump_bytes() dynamically controlled Implement only 'p' flag (_DPRINTK_FLAGS_PRINT) to keep it simple since hex dump prints multiple lines and long prefix would impact readability. To provide line/file etc. information, use pr_debug or similar before/after print_hex_dump_debug() Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/dynamic-debug-howto.txt')
1 files changed, 13 insertions, 2 deletions
diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt
index 6e1684981da2..72322c6d7352 100644
--- a/Documentation/dynamic-debug-howto.txt
+++ b/Documentation/dynamic-debug-howto.txt
@@ -6,8 +6,16 @@ This document describes how to use the dynamic debug (dyndbg) feature.
Dynamic debug is designed to allow you to dynamically enable/disable
kernel code to obtain additional kernel information. Currently, if
-CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_dbg() calls can
-be dynamically enabled per-callsite.
+CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_dbg() and
+print_hex_dump_debug()/print_hex_dump_bytes() calls can be dynamically
+enabled per-callsite.
+If CONFIG_DYNAMIC_DEBUG is not set, print_hex_dump_debug() is just
+shortcut for print_hex_dump(KERN_DEBUG).
+For print_hex_dump_debug()/print_hex_dump_bytes(), format string is
+its 'prefix_str' argument, if it is constant string; or "hexdump"
+in case 'prefix_str' is build dynamically.
Dynamic debug has even more useful features:
@@ -202,6 +210,9 @@ The flags are:
t Include thread ID in messages not generated from interrupt context
_ No flags are set. (Or'd with others on input)
+For print_hex_dump_debug() and print_hex_dump_bytes(), only 'p' flag
+have meaning, other flags ignored.
For display, the flags are preceded by '='
(mnemonic: what the flags are currently equal to).

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