| Message ID | 20221208142335.488382-1-hdegoede@redhat.com |
|---|---|
| Headers | show |
| Series | ACPI[CA]: fix ECDT EC probe ordering issues | expand |
Hi, On 12/8/22 17:51, Rafael J. Wysocki wrote: > Hi Hans, > > On Thu, Dec 8, 2022 at 3:23 PM Hans de Goede <hdegoede@redhat.com> wrote: >> >> Hi Rafael, >> >> As you requested in: >> https://github.com/acpica/acpica/pull/786#issuecomment-1342632326 >> >> Here is a non RFC version 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 >> >> including the ACPICA changes. >> >> This series is rebased on top of linux-pm/bleeding-edge, >> otherwise it is unchanged from the previous [RFC v3] version. >> >> From the original cover-letter of the previous [RFC v3] version: >> >> 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 > > I've applied the series and queued it up for 6.2. > > However, because I won't be able to do any kernel work before the next > week (most likely), it will not go into linux-next before Monday and I > would like it to spend at least a few days in it. This means that it > will be pushed in the second half of the merge window. Second half of the merge window is perfectly fine with me. Thank you for picking this up. Regards, Hans