Hans de Goede 41c80b8a63 i2c: designware: Never suspend i2c-busses used for accessing the system PMIC
Currently we are already setting a pm_runtime_disabled flag and disabling
runtime-pm for i2c-busses used for accessing the system PMIC on x86.
But this is not enough, there are ACPI opregions which may want to access
the PMIC during late-suspend and early-resume, so we need to completely
disable pm to be safe.

This commit renames the flag from pm_runtime_disabled to pm_disabled and
adds the following new behavior if the flag is set:

1) Call dev_pm_syscore_device(dev, true) which disables normal suspend /
   resume and remove the pm_runtime_disabled check from dw_i2c_plat_resume
   since that will now never get called. This fixes suspend_late handlers
   which use ACPI PMIC opregions causing errors like these:

  PM: Suspending system (freeze)
  PM: suspend of devices complete after 1127.751 msecs
  i2c_designware 808622C1:06: timeout waiting for bus ready
  ACPI Exception: AE_ERROR, Returned by Handler for [UserDefinedRegion]
  acpi 80860F14:02: Failed to change power state to D3hot
  PM: late suspend of devices failed

2) Set IRQF_NO_SUSPEND irq flag. This fixes resume_early handlers which
   handlers which use ACPI PMIC opregions causing errors like these:

  PM: resume from suspend-to-idle
  i2c_designware 808622C1:06: controller timed out
  ACPI Exception: AE_ERROR, Returned by Handler for [UserDefinedRegion]

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-03-22 09:53:24 +01:00
2017-02-13 12:24:56 -05:00
2016-05-23 17:04:14 -07:00
2017-03-19 19:09:39 -07:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.
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