Re: [PATCH v2] i2c: xiic: restore runtime PM teardown in remove to fix clk WARN flood

[Abdurrahman Hussain]

On Sun Aug 16, 2026 at 9:14 AM PDT, Andi Shyti wrote:
> Hi Abdurrahman,
>

Hi Andi,

On Sun, Aug 16, 2026 at 06:14:08PM +0200, Andi Shyti wrote:
> isn't devm_pm_runtime_set_active_enabled() calling
> pm_runtime_disable() + pm_runtime_set_suspended() +
> pm_runtime_dont_use_autosuspend() at teardown?

It does call all three, but the ordering defeats it, in two places:

1. Within the helper's own release, pm_runtime_disable_action() calls
   pm_runtime_dont_use_autosuspend() *before* pm_runtime_disable() --
   i.e. while runtime PM is still enabled.

2. devres is LIFO, and devm_clk_get_enabled() is registered before
   devm_pm_runtime_set_active_enabled() in probe(), so the clock's
   clk_disable_unprepare() release runs *after* the runtime-PM releases.

pm_runtime_put_sync() in remove() leaves the device RPM_ACTIVE with the
autosuspend timer armed: rpm_idle() falls through to
rpm_suspend(RPM_AUTO), the delay hasn't expired, so it just re-arms the
timer -- runtime_status stays ACTIVE and the clock stays enabled.

Then the devres teardown runs. pm_runtime_dont_use_autosuspend() clears
use_autosuspend; update_autosuspend() takes the else branch and calls
rpm_idle(RPM_AUTO), but now pm_runtime_autosuspend_expiration() returns
0, so rpm_suspend() no longer defers and suspends immediately --
xiic_i2c_runtime_suspend() clk_disable()s the clock, all while runtime
PM is still enabled. A moment later, further down the LIFO chain,
devm_clk_get_enabled()'s release does clk_disable_unprepare() on the
already-disabled clock and clk_core_disable() WARNs, once per device.

Calling pm_runtime_disable() in remove(), before any devres release
runs, closes that window: with runtime PM disabled the helper's
dont_use_autosuspend() can no longer trigger a suspend, so the clock
stays enabled and the clk release balances it cleanly.

You're right that set_suspended() and dont_use_autosuspend() are then
redundant with the helper -- pm_runtime_disable() is the only call that
has to happen early. So for v3 I'll drop those two and keep just
pm_runtime_disable() (with a short comment, and the full reasoning in
the commit log). Does that work for you?

Thanks,
Abdurrahman