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authorBrian Masney <bmasney@redhat.com>2023-04-11 22:21:53 +0300
committerJonathan Corbet <corbet@lwn.net>2023-04-21 02:53:38 +0300
commit54d85d6966ca1dafa0b05f163a425060e8be3120 (patch)
tree8d305e73e11936aeed530826233cec889b5b8e5f /Documentation/driver-api
parentc9b951c3136fb04a9bb89deef5bba8e262410f68 (diff)
downloadlinux-54d85d6966ca1dafa0b05f163a425060e8be3120.tar.xz
docs: clk: add documentation to log which clocks have been disabled
The existing clk documentation has a section that talks about the clk_ignore_unused kernel parameter. Add additional documentation that describes how to log which clocks the kernel disables on bootup. This will log messages like the following to the console on bootup: [ 1.268115] clk: Disabling unused clocks [ 1.272167] clk_disable: gcc_usb_clkref_en [ 1.276389] clk_disable: gcc_usb30_sec_sleep_clk [ 1.281131] clk_disable: gcc_usb30_prim_sleep_clk ... Signed-off-by: Brian Masney <bmasney@redhat.com> Link: https://lore.kernel.org/r/20230411192153.289688-1-bmasney@redhat.com [jc: turned parameters into a literal block] Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/clk.rst5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/driver-api/clk.rst b/Documentation/driver-api/clk.rst
index 3cad45d14187..93bab5336dfd 100644
--- a/Documentation/driver-api/clk.rst
+++ b/Documentation/driver-api/clk.rst
@@ -258,6 +258,11 @@ clocks properly but rely on them being on from the bootloader, bypassing
the disabling means that the driver will remain functional while the issues
are sorted out.
+You can see which clocks have been disabled by booting your kernel with these
+parameters::
+
+ tp_printk trace_event=clk:clk_disable
+
To bypass this disabling, include "clk_ignore_unused" in the bootargs to the
kernel.