Hi Hans, On Mon, Oct 3, 2022 at 4:42 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > > Hi All, > > Here is v3 of my series fixing some ECDT EC probe ordering issues which > are causing issues om some laptops: > > https://bugzilla.kernel.org/show_bug.cgi?id=214899 > > This is a RFC because fixing this requires some ACPICA changes which > obviously need to go upstream through the ACPICA project: > https://github.com/acpica/acpica/pull/786 I've just approved your pull request. Also, as soon as it gets merged, you can resubmit the series with a proper ACPICA commit ID and I will be able to apply the patches right away then. > The problem this fixed is best described by the commit message of patch 4: > > ACPI-2.0 says that the EC OpRegion handler must be available immediately > (like the standard default OpRegion handlers): > > Quoting from the ACPI spec version 6.3: "6.5.4 _REG (Region) ... > 2. OSPM must make Embedded Controller operation regions, accessed via > the Embedded Controllers described in ECDT, available before executing > any control method. These operation regions may become inaccessible > after OSPM runs _REG(EmbeddedControl, 0)." > > So acpi_bus_init() calls acpi_ec_ecdt_probe(), which calls > acpi_install_address_space_handler() to install the EC's OpRegion > handler, early on. > > This not only installs the OpRegion handler, but also calls the EC's > _REG method. The _REG method call is a problem because it may rely on > initialization done by the _INI methods of one of the PCI / _SB root devs, > see for example: https://bugzilla.kernel.org/show_bug.cgi?id=214899 . > > Generally speaking _REG methods are executed when the ACPI-device they > are part of has a driver bound to it. Where as _INI methods must be > executed at table load time (according to the spec). The problem here > is that the early acpi_install_address_space_handler() call causes > the _REG handler to run too early. > > To allow fixing this the ACPICA code now allows to split the OpRegion > handler installation and the executing of _REG into 2 separate steps. > > This commit uses this ACPICA functionality to fix the EC probe ordering > by delaying the executing of _REG for ECDT described ECs till the matching > EC device in the DSDT gets parsed and acpi_ec_add() for it gets called. > This moves the calling of _REG for the EC on devices with an ECDT to > the same point in time where it is called on devices without an ECDT table. > > Changes in v3: > - Add a prep patch to fix an indentation issue in Linux' acpixf.h to fix > the patch from ACPICA's script not applying > - Add 2 new functions to ACPICA for this instead of a flags argument > 1. acpi_install_address_space_handler_no_reg() > 2. acpi_execute_reg_methods() > - Add a patch to fix EC handler removal in the ECDT case > > From my pov this series is ready for merging once the ACPICA changes > are accepted. I agree, please resubmit as soon as the upstream ACPICA pull request gets merged. Thanks!
