Quoting Uwe Kleine-König (2022-10-26 08:18:12)
> Allow to pass an integer n that results in only keeping n unused clocks
> enabled.
>
> This helps to debug the problem if you only know that clk_ignore_unused
> helps but you have no clue yet which clock is the culprit.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
> Hello,
>
> compared to v2 sent in August 2021 this is a trivial rebase on top of
> v6.1-rc1. I pinged that one repeatedly, I'm now trying with resending
> and calling the rebased patch v3 to maybe get some feedback. :-\
>
> Best regards
> Uwe
>
> Documentation/driver-api/clk.rst | 4 +++-
No update to Documentation/admin-guide/kernel-parameters.txt?
> drivers/clk/clk.c | 33 ++++++++++++++++++++++++--------
> 2 files changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index c3c3f8c07258..356119a7e5fe 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1322,6 +1322,8 @@ static void __init clk_unprepare_unused_subtree(struct clk_core *core)
> clk_pm_runtime_put(core);
> }
>
> +static unsigned clk_unused_keep_on __initdata;
> +
> static void __init clk_disable_unused_subtree(struct clk_core *core)
> {
> struct clk_core *child;
> @@ -1352,12 +1354,17 @@ static void __init clk_disable_unused_subtree(struct clk_core *core)
> * back to .disable
> */
> if (clk_core_is_enabled(core)) {
> - trace_clk_disable(core);
> - if (core->ops->disable_unused)
> - core->ops->disable_unused(core->hw);
> - else if (core->ops->disable)
> - core->ops->disable(core->hw);
> - trace_clk_disable_complete(core);
> + if (clk_unused_keep_on) {
> + pr_warn("Keep unused clk \"%s\" on\n", core->name);
> + clk_unused_keep_on -= 1;
> + } else {
> + trace_clk_disable(core);
We have trace_clk_disable() here. Can you have this tracepoint print to
the kernel log and watch over serial console? That would be faster than
bisecting.
> + if (core->ops->disable_unused)
> + core->ops->disable_unused(core->hw);
> + else if (core->ops->disable)
> + core->ops->disable(core->hw);
> + trace_clk_disable_complete(core);
> + }
> }
>
> unlock_out:
> @@ -1369,9 +1376,17 @@ static void __init clk_disable_unused_subtree(struct clk_core *core)
> }
>
> static bool clk_ignore_unused __initdata;
> -static int __init clk_ignore_unused_setup(char *__unused)
> +static int __init clk_ignore_unused_setup(char *keep)
> {
> - clk_ignore_unused = true;
> + if (*keep == '=') {
> + int ret;
> +
> + ret = kstrtouint(keep + 1, 0, &clk_unused_keep_on);
> + if (ret < 0)
Could omit 'ret' and just have if (kstrtouint(..))
> + pr_err("Warning: failed to parse clk_ignore_unused parameter, ignoring");
Missing newline on printk.
> + } else {
> + clk_ignore_unused = true;
> + }
> return 1;
> }
> __setup("clk_ignore_unused", clk_ignore_unused_setup);
