kernel/drivers/acpi/glue.c, branch 0x221E-v0.0.1-v6.19

ACPI: Fix selecting wrong ACPI fwnode for the iGPU on some Dell laptops

2023-01-10T19:23:48Z

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 Signed-off-by: Hans de Goede Cc: 6.1+ # 6.1+ Signed-off-by: Rafael J. Wysocki

ACPI: glue: Introduce acpi_find_child_by_adr()

2022-06-20T18:28:48Z

Rearrange the ACPI device lookup code used internally by acpi_find_child_device() so it can avoid extra checks after finding one object with a matching _ADR and use it for defining acpi_find_child_by_adr() that will allow the callers to find a given ACPI device's child matching a given bus address without doing any other checks in check_one_child(). Signed-off-by: Rafael J. Wysocki Reviewed-by: Andy Shevchenko

ACPI: glue: Introduce acpi_dev_has_children()

2022-06-20T18:28:48Z

Define acpi_dev_has_children() as a wrapper around acpi_dev_for_each_child() and use it to check if the given ACPI device has any children instead of checking the children list head in struct acpi_device. This will help to eliminate the children list head from struct acpi_device as it is redundant and it is used in questionable ways in some places (in particular, locking is needed for walking the list pointed to it safely, but it is often missing). Signed-off-by: Rafael J. Wysocki Reviewed-by: Andy Shevchenko

ACPI: glue: Use acpi_dev_for_each_child()

2022-06-20T18:28:48Z

Instead of walking the list of children of an ACPI device directly, use acpi_dev_for_each_child() to carry out an action for all of the given ACPI device's children. This will help to eliminate the children list head from struct acpi_device as it is redundant and it is used in questionable ways in some places (in particular, locking is needed for walking the list pointed to it safely, but it is often missing). Signed-off-by: Rafael J. Wysocki Reviewed-by: Andy Shevchenko

ACPI: glue: Rearrange find_child_checks()

2022-05-12T14:52:32Z

Notice that it is not necessary to evaluate _STA in find_child_checks() if the device is expected to have children, but there are none, so move the children check to the front of the function. Also notice that FIND_CHILD_MIN_SCORE can be returned right away if _STA is missing, so make the function do so. Finally, replace the ternary operator in the return statement argument with an if () and a standalone return which is somewhat easier to follow. Signed-off-by: Rafael J. Wysocki

Revert "ACPI: scan: Release PM resources blocked by unused objects"

2021-11-17T16:05:41Z

Revert commit c10383e8ddf4 ("ACPI: scan: Release PM resources blocked by unused objects"), because it causes boot issues to appear on some platforms. Reported-by: Kyle D. Pelton Reported-by: Saranya Gopal Signed-off-by: Rafael J. Wysocki

Merge branches 'acpi-glue', 'acpi-pnp', 'acpi-processor' and 'acpi-soc'

2021-11-02T17:36:40Z

Merge updates of the code associating ACPI device objects with devices and PNP code, processor driver, and Intel LPSS driver updates for 5.16-rc1: - Make the association of ACPI device objects with PCI devices more straightforward and simplify the code doing that for all devices in general (Rafael Wysocki). - Use acpi_device_adr() in acpi_find_child_device() instead of evaluating _ADR (Rafael Wysocki). - Drop duplicate device IDs from PNP device IDs list (Krzysztof Kozlowski). - Allow acpi_idle_play_dead() to use C3 on AMD processors (Richard Gong). - Use ACPI_COMPANION() to simplify code in the ACPI driver for Intel SoCs (Rafael Wysocki). * acpi-glue: ACPI: glue: Use acpi_device_adr() in acpi_find_child_device() ACPI: glue: Look for ACPI bus type only if ACPI companion is not known ACPI: glue: Drop cleanup callback from struct acpi_bus_type PCI: ACPI: Drop acpi_pci_bus * acpi-pnp: ACPI: PNP: remove duplicated BRI0A49 and BDP3336 entries * acpi-processor: ACPI: processor idle: Allow playing dead in C3 state * acpi-soc: ACPI: LPSS: Use ACPI_COMPANION() directly

ACPI: glue: Use acpi_device_adr() in acpi_find_child_device()

2021-10-28T14:53:24Z

Instead of evaluating _ADR in acpi_find_child_device(), use the observation that it has already been evaluated and the value returned by it has been stored in the pnp.type.bus_address field of the ACPI device object at hand. Signed-off-by: Rafael J. Wysocki

ACPI: scan: Release PM resources blocked by unused objects

2021-10-13T17:57:01Z

On some systems the ACPI namespace contains device objects that are not used in certain configurations of the system. If they start off in the D0 power state configuration, they will stay in it until the system reboots, because of the lack of any mechanism possibly causing their configuration to change. If that happens, they may prevent some power resources from being turned off or generally they may prevent the platform from getting into the deepest low-power states thus causing some energy to be wasted. Address this issue by changing the configuration of unused ACPI device objects to the D3cold power state one after carrying out the ACPI-based enumeration of devices. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=214091 Link: https://lore.kernel.org/linux-acpi/20211007205126.11769-1-mario.limonciello@amd.com/ Reported-by: Mario Limonciello Signed-off-by: Rafael J. Wysocki Tested-by: Mario Limonciello

ACPI: glue: Look for ACPI bus type only if ACPI companion is not known

2021-09-27T15:01:37Z

Notice that it is not necessary to look for the "ACPI bus type" of the device in acpi_device_notify() if the device's ACPI companion is set upfront, so modify the code to do that lookup only if it is necessary to find the ACPI companion. Also notice that if the device's ACPI companion is not set upfront in acpi_device_notify(), the device cannot be either a PCI one or a platform one, so check for these bus types only if the device's ACPI companion is set. Signed-off-by: Rafael J. Wysocki Tested-by: Ferry Toth