[PATCH] ACPI: PM: Add Acer Aspire A515-53G to dmi_leave_unused_power_resources_on

[PATCH] ACPI: PM: Add Acer Aspire A515-53G to dmi_leave_unused_power_resources_on

[Krittikun Wongnin]

On the Acer Aspire A515-53G (Whiskey Lake + NVIDIA GeForce MX230), the
dGPU behind root port RP05 (00:1c.4) falls off the bus during boot and
is unusable until the next power cycle:

  nvidia 0000:02:00.0: Unable to change power state from D3cold to D0, device inaccessible
  NVRM: The NVIDIA GPU 0000:02:00.0 ... has fallen off the bus

The firmware ships two SSDTs which both provide power management for
the dGPU:

 - One SSDT defines \_SB.PCI0.RP05.PC01 together with
   RP05._PR0/_PR2/_PR3 = { PC01 }.

 - A second SSDT defines \_SB.PCI0.RP05.PCRP (_STA initially One,
   _OFF calls \_SB.PCI0.HGOF, which puts the link into L2/L3 and drops
   the dGPU power enable GPIO) and its own RP05._PR0/_PR2/_PR3/_S0W.
   The latter fail to load:

     ACPI BIOS Error (bug): Failure creating named object [\_SB.PCI0.RP05._PR0], AE_ALREADY_EXISTS

As a result PCRP is not referenced by any device and
acpi_turn_off_unused_power_resources() turns it off right after the
ACPI namespace scan. This cuts power to the dGPU, but PC01 still
believes it is on, so its _ON method is a no-op when the PCI core later
tries to bring the GPU back to D0.

Windows does not turn off unused power resources, so the dGPU works
there.

Add the machine to dmi_leave_unused_power_resources_on, like the
THUNDEROBOT ZERO which has a similar SSDT bug. With this change the
dGPU stays on the bus and the nvidia driver binds. Runtime PM of the
dGPU is unaffected, as it is handled through PC01: with no driver
bound and power/control set to auto, RP05 reaches D3cold and the GPU
comes back to D0 on resume.

Link: https://lore.kernel.org/r/CADS-TgDQ1G8vrTQLJeQ3RTBVFTyMe0C+5p2=UBKS=EFCDFuaxw@mail.gmail.com/
Signed-off-by: Krittikun Wongnin <krittikunwongnin@gmail.com>
---
 drivers/acpi/power.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index 23a4e207a..cf36dee56 100644
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -1121,6 +1121,19 @@ static const struct dmi_system_id dmi_leave_unused_power_resources_on[] = {
 		}
 
 	},
+	{
+		/*
+		 * Acer Aspire A515-53G: Two SSDTs both define power resources
+		 * for the dGPU root port RP05 ('PC01' and 'PCRP'). Only PC01 ends
+		 * up in RP05's _PR0/_PR3, so 'PCRP' is shut down on
+		 * initialization, cutting power to the NVIDIA dGPU behind the
+		 * back of 'PC01' and making the dGPU unavailable.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire A515-53G"),
+		},
+	},
 	{}
 };
 
-- 
2.55.0

Re: [PATCH] ACPI: PM: Add Acer Aspire A515-53G to dmi_leave_unused_power_resources_on

[sashiko-bot]

> On the Acer Aspire A515-53G (Whiskey Lake + NVIDIA GeForce MX230), the
> dGPU behind root port RP05 (00:1c.4) falls off the bus during boot and
> is unusable until the next power cycle:
> 
>   nvidia 0000:02:00.0: Unable to change power state from D3cold to D0, device inaccessible
>   NVRM: The NVIDIA GPU 0000:02:00.0 ... has fallen off the bus
> 
> The firmware ships two SSDTs which both provide power management for
> the dGPU:
> 
>  - One SSDT defines \_SB.PCI0.RP05.PC01 together with
>    RP05._PR0/_PR2/_PR3 = { PC01 }.
> 
>  - A second SSDT defines \_SB.PCI0.RP05.PCRP (_STA initially One,
>    _OFF calls \_SB.PCI0.HGOF, which puts the link into L2/L3 and drops
> [ ... ]
> bound and power/control set to auto, RP05 reaches D3cold and the GPU
> comes back to D0 on resume.
> 
> Link: https://lore.kernel.org/r/CADS-TgDQ1G8vrTQLJeQ3RTBVFTyMe0C+5p2=UBKS=EFCDFuaxw@mail.gmail.com/
> Signed-off-by: Krittikun Wongnin <krittikunwongnin@gmail.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261013074245.4327-1-krittikunwongnin@gmail.com?part=1