From: Hans de Goede hdegoede@redhat.com
commit f64e4275ef7407d5c3eca20436519bbd1f796e40 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/glue.c | 14 ++++++++++++-- drivers/acpi/scan.c | 7 +++++-- include/acpi/acpi_bus.h | 3 ++- 3 files changed, 19 insertions(+), 5 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; diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 274344434282..0c6f06abe3f4 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -1370,9 +1370,12 @@ static void acpi_set_pnp_ids(acpi_handle handle, struct acpi_device_pnp *pnp, * Some devices don't reliably have _HIDs & _CIDs, so add * synthetic HIDs to make sure drivers can find them. */ - if (acpi_is_video_device(handle)) + if (acpi_is_video_device(handle)) { acpi_add_id(pnp, ACPI_VIDEO_HID); - else if (acpi_bay_match(handle)) + pnp->type.backlight = 1; + break; + } + if (acpi_bay_match(handle)) acpi_add_id(pnp, ACPI_BAY_HID); else if (acpi_dock_match(handle)) acpi_add_id(pnp, ACPI_DOCK_HID); diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h index cd3b75e08ec3..e44be31115a6 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -230,7 +230,8 @@ struct acpi_pnp_type { u32 hardware_id:1; u32 bus_address:1; u32 platform_id:1; - u32 reserved:29; + u32 backlight:1; + u32 reserved:28; };
struct acpi_device_pnp {