This is a note to let you know that I've just added the patch titled ACPI / scan: Prefer devices without _HID for _ADR matching to the 4.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: acpi-scan-prefer-devices-without-_hid-for-_adr-matching.patch and it can be found in the queue-4.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fdad4e7a876a2cb3d2c1f04e5418c324e79fffef Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx> Date: Sat, 1 Apr 2017 00:45:52 +0200 Subject: ACPI / scan: Prefer devices without _HID for _ADR matching From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> commit fdad4e7a876a2cb3d2c1f04e5418c324e79fffef upstream. Commit c2a6bbaf0c5f (ACPI / scan: Prefer devices without _HID/_CID for _ADR matching) added a list_empty(&adev->pnp.ids) check to find_child_checks() so as to catch situations in which the ACPI core attempts to decode _ADR for a device having a _HID too which is strictly against the spec. However, it overlooked the fact that the adev->pnp.ids list for the devices taken into account by find_child_checks() may contain device IDs set internally by the kernel, like "LNXVIDEO" (thanks to Zhang Rui for that realization), and it broke the enumeration of those devices as a result. To unbreak it, replace the overly coarse grained list_empty() check with a much more precise check against the pnp.type.platform_id flag which is only set for devices having a _HID (that's how it should be done from the start, as having both _ADR and _CID is actually permitted). Fixes: c2a6bbaf0c5f (ACPI / scan: Prefer devices without _HID/_CID for _ADR matching) Link: https://bugzilla.kernel.org/show_bug.cgi?id=194889 Reported-and-tested-by: Mike <mike@xxxxxxxxxxxxxxxx> Tested-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/acpi/glue.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/drivers/acpi/glue.c +++ b/drivers/acpi/glue.c @@ -99,13 +99,13 @@ static int find_child_checks(struct acpi return -ENODEV; /* - * If the device has a _HID (or _CID) returning a valid ACPI/PNP - * device ID, it is better to make it look less attractive here, so that - * the other device with the same _ADR value (that may not have a valid - * device ID) can be matched going forward. [This means a second spec - * violation in a row, so whatever we do here is best effort anyway.] + * If the device has a _HID returning a valid ACPI/PNP device ID, it is + * better to make it look less attractive here, so that the other device + * with the same _ADR value (that may not have a valid device ID) can be + * matched going forward. [This means a second spec violation in a row, + * so whatever we do here is best effort anyway.] */ - return sta_present && list_empty(&adev->pnp.ids) ? + return sta_present && !adev->pnp.type.platform_id ? FIND_CHILD_MAX_SCORE : FIND_CHILD_MIN_SCORE; } Patches currently in stable-queue which might be from rafael.j.wysocki@xxxxxxxxx are queue-4.10/acpi-scan-prefer-devices-without-_hid-for-_adr-matching.patch