doc/kernel-parameters.txt: clarify clk_ignore_unused

Refine the definition around clk_ignore_unused, which caused some
confusion recently on the linux-fbdev and linux-arm-kernel mailing
lists[0].

[0] http://lkml.kernel.org/r/<20140929135358.GC30998@ulmo>

Signed-off-by: Mike Turquette <mturquette@linaro.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 10d51c2f10d7..0ce01fb286c4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -605,11 +605,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         See Documentation/s390/CommonIO for details.
         clk_ignore_unused
                         [CLK]
-                        Keep all clocks already enabled by bootloader on,
-                        even if no driver has claimed them. This is useful
-                        for debug and development, but should not be
-                        needed on a platform with proper driver support.
-                        For more information, see Documentation/clk.txt.
+                        Prevents the clock framework from automatically gating
+                        clocks that have not been explicitly enabled by a Linux
+                        device driver but are enabled in hardware at reset or
+                        by the bootloader/firmware. Note that this does not
+                        force such clocks to be always-on nor does it reserve
+                        those clocks in any way. This parameter is useful for
+                        debug and development, but should not be needed on a
+                        platform with proper driver support.  For more
+                        information, see Documentation/clk.txt.
 
         clock=          [BUGS=X86-32, HW] gettimeofday clocksource override.
                         [Deprecated]