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author | Hans de Goede <hdegoede@redhat.com> | 2023-01-10 16:30:28 +0100 |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2023-01-10 20:23:48 +0100 |
commit | f64e4275ef7407d5c3eca20436519bbd1f796e40 (patch) | |
tree | 44fa2f995c4a6e4f795434f930730688a5a35e09 /drivers/acpi/glue.c | |
parent | b7bfaa761d760e72a969d116517eaa12e404c262 (diff) | |
download | linux-f64e4275ef7407d5c3eca20436519bbd1f796e40.tar.gz linux-f64e4275ef7407d5c3eca20436519bbd1f796e40.tar.bz2 linux-f64e4275ef7407d5c3eca20436519bbd1f796e40.zip |
ACPI: Fix selecting wrong ACPI fwnode for the iGPU on some Dell laptops
The Dell Latitude E6430 both with and without the optional NVidia dGPU
has a bug in its ACPI tables which is causing Linux to assign the wrong
ACPI fwnode / companion to the pci_device for the i915 iGPU.
Specifically under the PCI root bridge there are these 2 ACPI Device()s :
Scope (_SB.PCI0)
{
Device (GFX0)
{
Name (_ADR, 0x00020000) // _ADR: Address
}
...
Device (VID)
{
Name (_ADR, 0x00020000) // _ADR: Address
...
Method (_DOS, 1, NotSerialized) // _DOS: Disable Output Switching
{
VDP8 = Arg0
VDP1 (One, VDP8)
}
Method (_DOD, 0, NotSerialized) // _DOD: Display Output Devices
{
...
}
...
}
}
The non-functional GFX0 ACPI device is a problem, because this gets
returned as ACPI companion-device by acpi_find_child_device() for the iGPU.
This is a long standing problem and the i915 driver does use the ACPI
companion for some things, but works fine without it.
However since commit 63f534b8bad9 ("ACPI: PCI: Rework acpi_get_pci_dev()")
acpi_get_pci_dev() relies on the physical-node pointer in the acpi_device
and that is set on the wrong acpi_device because of the wrong
acpi_find_child_device() return. This breaks the ACPI video code,
leading to non working backlight control in some cases.
Add a type.backlight flag, mark ACPI video bus devices with this and make
find_child_checks() return a higher score for children with this flag set,
so that it picks the right companion-device.
Fixes: 63f534b8bad9 ("ACPI: PCI: Rework acpi_get_pci_dev()")
Co-developed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: 6.1+ <stable@vger.kernel.org> # 6.1+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/glue.c')
-rw-r--r-- | drivers/acpi/glue.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c index 204fe94c7e45..a194f30876c5 100644 --- a/drivers/acpi/glue.c +++ b/drivers/acpi/glue.c @@ -75,7 +75,8 @@ static struct acpi_bus_type *acpi_get_bus_type(struct device *dev) } #define FIND_CHILD_MIN_SCORE 1 -#define FIND_CHILD_MAX_SCORE 2 +#define FIND_CHILD_MID_SCORE 2 +#define FIND_CHILD_MAX_SCORE 3 static int match_any(struct acpi_device *adev, void *not_used) { @@ -96,8 +97,17 @@ static int find_child_checks(struct acpi_device *adev, bool check_children) return -ENODEV; status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta); - if (status == AE_NOT_FOUND) + if (status == AE_NOT_FOUND) { + /* + * Special case: backlight device objects without _STA are + * preferred to other objects with the same _ADR value, because + * it is more likely that they are actually useful. + */ + if (adev->pnp.type.backlight) + return FIND_CHILD_MID_SCORE; + return FIND_CHILD_MIN_SCORE; + } if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED)) return -ENODEV; |