5adc409340
x86 ACPI boards which ship with only Android as their factory image usually have pretty broken ACPI tables, relying on everything being hardcoded in the factory kernel image and often disabling parts of the ACPI enumeration kernel code to avoid the broken tables causing issues. Part of this broken ACPI code is that sometimes these boards have _AEI ACPI GPIO event handlers which are broken. So far this has been dealt with in the platform/x86/x86-android-tablets.c module, which contains various workarounds for these devices, by it calling acpi_gpiochip_free_interrupts() on gpiochip-s with troublesome handlers to disable the handlers. But in some cases this is too late, if the handlers are of the edge type then gpiolib-acpi.c's code will already have run them at boot. This can cause issues such as GPIOs ending up as owned by "ACPI:OpRegion", making them unavailable for drivers which actually need them. Boards with these broken ACPI tables are already listed in drivers/acpi/x86/utils.c for e.g. acpi_quirk_skip_i2c_client_enumeration(). Extend the quirks mechanism for a new acpi_quirk_skip_gpio_event_handlers() helper, this re-uses the DMI-ids rather then having to duplicate the same DMI table in gpiolib-acpi.c . Also add the new ACPI_QUIRK_SKIP_GPIO_EVENT_HANDLERS quirk to existing boards with troublesome ACPI gpio event handlers, so that the current acpi_gpiochip_free_interrupts() hack can be removed from x86-android-tablets.c . Signed-off-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
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.