Re: [PATCH v4] i2c: designware: Fix unbalanced suspended flag

From: Jarkko Nikula
Date: Mon Dec 19 2022 - 10:01:29 EST


On 12/19/22 15:10, Andy Shevchenko wrote:
On Mon, Dec 19, 2022 at 01:01:45PM +0000, Richard Fitzgerald wrote:
Ensure that i2c_mark_adapter_suspended() is always balanced by a call to
i2c_mark_adapter_resumed().

dw_i2c_plat_resume() must always be called, so that
i2c_mark_adapter_resumed() is called. This is not compatible with
DPM_FLAG_MAY_SKIP_RESUME, so remove the flag.

Since the controller is always resumed on system resume the
dw_i2c_plat_complete() callback is redundant and has been removed.

The unbalanced suspended flag was introduced by commit c57813b8b288
("i2c: designware: Lock the adapter while setting the suspended flag")

Before that commit, the system and runtime PM used the same functions. The
DPM_FLAG_MAY_SKIP_RESUME was used to skip the system resume if the driver
had been in runtime-suspend. If system resume was skipped, the suspended
flag would be cleared by the next runtime resume. The check of the
suspended flag was _after_ the call to pm_runtime_get_sync() in
i2c_dw_xfer(). So either a system resume or a runtime resume would clear
the flag before it was checked.

Having introduced the unbalanced suspended flag with that commit, a further
commit 80704a84a9f8
("i2c: designware: Use the i2c_mark_adapter_suspended/resumed() helpers")

This is still unwrapped propertly, but no need to resend, it so minor, really.
Just a hint for the future submissions.

This version was working on those two machines that saw a regression with v2 so

Acked-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>