4222cc9e79
[ Upstream commit e1d9148582ab2c3dada5c5cf8ca7531ca269fee5 ] Microsoft introduced support in Windows XP for blocking port I/O to various regions. For Windows compatibility ACPICA has adopted the same protections and will disallow writes to those (presumably) the same regions. On some systems the AML included with the firmware will issue 4 byte long writes to 0x80. These writes aren't making it over because of this blockage. The first 4 byte write attempt is rejected, and then subsequently 1 byte at a time each offset is tried. The first at 0x80 works, but then the next 3 bytes are rejected. This manifests in bizarre failures for devices that expected the AML to write all 4 bytes. Trying the same AML on Windows 10 or 11 doesn't hit this failure and all 4 bytes are written. Either some of these regions were wrong or some point after Windows XP some of these regions blocks have been lifted. In the last 15 years there doesn't seem to be any reports popping up of this error in the Windows event viewer anymore. There is no documentation at Microsoft's developer site indicating that Windows ACPI interpreter blocks these regions. Between the lack of documentation and the fact that the writes actually do work in Windows 10 and 11, it's quite likely Windows doesn't actually enforce this anymore. So to help the issue, only enforce Windows XP specific entries if the latest _OSI supported is Windows XP. Continue to enforce the ALWAYS_ILLEGAL entries. Link: https://github.com/acpica/acpica/pull/817 Fixes: 7f0719039085 ("ACPICA: New: I/O port protection") Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.