ACPI: PM: Add HP EliteBook 855 G7 WWAN modem power resource quirk

This laptop (and possibly similar models too) has power resource called
"GP12.PXP_" for its Intel XMM7360 WWAN modem.

For this power resource to turn ON power for the modem it needs certain
internal flag called "ONEN" to be set:

Method (_ON, 0, NotSerialized) // _ON_: Power On
{
	If (^^^LPCB.EC0.ECRG)
	{
		If ((ONEN == Zero))
		{
                        Return (Zero)
		}
(..)
	}
}

This flag only gets set from this power resource _OFF method, while
the actual modem power gets turned off during suspend by "GP12.PTS"
method called from the global _PTS (Prepare To Sleep) method.

In fact, this power resource _OFF method implementation just sets the
aforementioned flag:

Method (_OFF, 0, NotSerialized) // _OFF: Power Off
{
	OFEN = Zero
	ONEN = One
}

Upon hibernation finish, the kernel tries to set this power resource
back ON since its _STA method returns 0 and the resource is still
considered in use as it is declared as required for D0 for both the
modem ACPI device (GP12.PWAN) and its parent PCIe port ACPI device
object (GP12).  But the _ON method won't do anything since that "ONEN"
flag is not set.

Overall, this means the modem is dead after hibernation finish until the
laptop is rebooted since the modem power has been cut by _PTS and its
PCI configuration was lost and not able to be restored.

The easiest way to workaround this issue is to call this power resource
_OFF method before calling the _ON method to make sure the "ONEN" flag
gets properly set.

This makes the modem alive once again after hibernation finish - with
properly restored PCI configuration space.

Since this platform does *not* support S3 the fact that
acpi_resume_power_resources() is also called during resume from S3 is
not a problem there.

Do the DMI based quirk matching and quirk flag initialization just
once - in acpi_power_resources_init() function.

This way the whole resume path overhead of this change on other systems
amounts to simple hp_eb_gp12pxp_quirk flag comparison.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Link: https://patch.msgid.link/c6ff6931c5d27592052f30339de1b9cc298c43f0.1754243159.git.mail@maciej.szmigiero.name
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

0 files changed, 0 insertions, 0 deletions