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ACPI: video: Put ACPI video and its child devices into D0 on boot

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Screen brightness can only be changed once on HP ZBook Fury 16 G10.

The vendor reports that the issue is related to the fact that Linux doesn't
invoke _PS0 at boot for all ACPI devices, as expected by the platform firmware:

    Scope (\_SB.PC00.GFX0)
    {
        Scope (DD1F)
        {
            Method (_PS0, 0, Serialized)  // _PS0: Power State 0
            {
                If (CondRefOf (\_SB.PC00.LPCB.EC0.SSBC))
                {
                    \_SB.PC00.LPCB.EC0.SSBC ()
                }
            }
	    ...
	}
	...
    }

The \_SB.PC00.GFX0.DD1F is the panel device, and its _PS0 needs to be
executed at the initialization time to make the brightness control work
properly.

_PS0 is not evaluated for this device, because _PSC is missing,
which violates the ACPI specification (ACPI 6.5, section 7.3.6).

Commit b378549226 ("ACPI / PM: Do not power manage devices in unknown
initial states") tried to work around missing _PSC on platforms with
defective firmware, but got reverted due to a regression.

So the safest approach is to use acpi_device_fix_up_power_extended() to
put ACPI video and its child devices to D0 to address the issue at hand.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217683
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Kai-Heng Feng 2023-07-21 23:21:43 +08:00 committed by Rafael J. Wysocki
parent 96b709be18
commit 89c290ea75
1 changed files with 6 additions and 0 deletions
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6
drivers/acpi/acpi_video.c
View File

@ -2027,6 +2027,12 @@ static int acpi_video_bus_add(struct acpi_device *device)
if (error)
goto err_put_video;
/*
* HP ZBook Fury 16 G10 requires ACPI video's child devices have _PS0
* evaluated to have functional panel brightness control.
*/
acpi_device_fix_up_power_extended(device);
pr_info("%s [%s] (multi-head: %s rom: %s post: %s)\n",
ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
video->flags.multihead ? "yes" : "no",