From 54d85d6966ca1dafa0b05f163a425060e8be3120 Mon Sep 17 00:00:00 2001 From: Brian Masney Date: Tue, 11 Apr 2023 15:21:53 -0400 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20230411192153.289688-1-bmasney@redhat.com [jc: turned parameters into a literal block] Signed-off-by: Jonathan Corbet --- Documentation/driver-api/clk.rst | 5 +++++ 1 file changed, 5 insertions(+) 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.