lkml.org 
[lkml]   [2022]   [Dec]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v4] i2c: designware: Fix unbalanced suspended flag
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.

> changed from using a local suspended flag to using the
> i2c_mark_adapter_suspended/resumed() functions. These use a flag that is
> checked by I2C core code before issuing the transfer to the bus driver, so
> there was no opportunity for the bus driver to runtime resume itself before
> the flag check.

...

> ---
> Changes from v3:
> - Fixed wrapping in commit description. No code changes

Thank you, but see the above :-)

--
With Best Regards,
Andy Shevchenko


\
 
 \ /
  Last update: 2022-12-19 14:11    [W:0.087 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site