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As the comment above the code setting the DPM_FLAG_NO_DIRECT_COMPLETE
flag explains:
/*
* On Cherry Trail devices the GFX0._PS0 AML checks if the controller
* is on and if it is not on it turns it on and restores what it
* believes is the correct state to the PWM controller.
* Because of this we must disallow direct-complete, which keeps the
* controller (runtime)suspended, on resume to avoid 2 issues:
* 1. The controller getting turned on without the linux-pm code
* knowing about this. On devices where the controller is unused
* this causes it to stay on during the next suspend causing high
* battery drain (because S0i3 is not reached)
* 2. The state restoring code unexpectedly messing with the controller
*/
The pm-core must not skip resume to avoid the GFX0._PS0 AML code messing
with the PWM controller behind our back. But leaving the controller
runtime-suspended (skipping runtime-resume + normal-suspend) during
suspend is fine. Set the DPM_FLAG_SMART_SUSPEND flag to allow this.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.