Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
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In some cases ACPI control methods used during device enumeration (such as _HID or _STA) may rely on Operation Region handlers supplied by the drivers of other devices [1]: An example of this is the Acer Switch 10E SW3-016 model. The _HID method of the ACPI node for the UART attached Bluetooth, reads GPIOs to detect the installed wifi chip and update the _HID for the Bluetooth's ACPI node accordingly. The current ACPI scan code calls _HID before the GPIO controller's OpRegions are available, leading to the wrong _HID being used and Bluetooth not working. In principle, in those cases there should be a _DEP control method under the device object with OpRegion enumeration dependencies, so deferring the enumeration of devices with _DEP returning a non-empty list of suppliers of OpRegions depended on by the given device (modulo some known exceptions that don't really supply any OpRegions and are listed by _DEP for other reasons irrelevant for Linux) should at least address the first-order dependencies by allowing the OpRegion suppliers to be enumerated before their consumers. Implement the above idea by modifying acpi_bus_scan() to enumerate devices in the given scope of the ACPI namespace in two passes, where the first pass covers the devices without "significant" lists of dependencies coming from _DEP only and the second pass covers all of the devices that were not enumerated in the first pass. Take _DEP into account only for device objects with _HID, mostly in order to avoid deferring the creation of ACPI device objects that represent PCI devices and must be present during the enumeration of the PCI bus (which takes place during the processing of the ACPI device object that represents the host bridge), so that they can be properly associated with the corresponding PCI devices. Link: https://lore.kernel.org/linux-acpi/20201121203040.146252-1-hdegoede@redhat.com/ # [1] Reported-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Hans de Goede <hdegoede@redhat.com> Tested-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> |
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README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.