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commit 59348401ebed ("platform/x86: amd-pmc: Add special handling for
timer based S0i3 wakeup") adds support for using another platform timer
in lieu of the RTC which doesn't work properly on some systems. This path
was validated and worked well before submission. During the 5.16-rc1 merge
window other patches were merged that caused this to stop working properly.
When this feature was used with 5.16-rc1 or later some OEM laptops with the
matching firmware requirements from that commit would shutdown instead of
program a timer based wakeup.
This was bisected to commit 8d89835b0467 ("PM: suspend: Do not pause
cpuidle in the suspend-to-idle path"). This wasn't supposed to cause any
negative impacts and also tested well on both Intel and ARM platforms.
However this changed the semantics of when CPUs are allowed to be in the
deepest state. For the AMD systems in question it appears this causes a
firmware crash for timer based wakeup.
It's hypothesized to be caused by the `amd-pmc` driver sending `OS_HINT`
and all the CPUs going into a deep state while the timer is still being
programmed. It's likely a firmware bug, but to avoid it don't allow setting
CPUs into the deepest state while using CZN timer wakeup path.
If later it's discovered that this also occurs from "regular" suspends
without a timer as well or on other silicon, this may be later expanded to
run in the suspend path for more scenarios.
Cc: stable@vger.kernel.org # 5.16+
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/linux-acpi/BL1PR12MB51570F5BD05980A0DCA1F3F4E23A9@BL1PR12MB5157.namprd12.prod.outlook.com/T/#mee35f39c41a04b624700ab2621c795367f19c90e
Fixes: 8d89835b0467 ("PM: suspend: Do not pause cpuidle in the suspend-to-idle path")
Fixes: 23f62d7ab25b ("PM: sleep: Pause cpuidle later and resume it earlier during system transitions")
Fixes: 59348401ebed ("platform/x86: amd-pmc: Add special handling for timer based S0i3 wakeup"
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20220223175237.6209-1-mario.limonciello@amd.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.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.