tree dca33e94a1a528f6ba29ebb988aadd233e09e544
parent c6bc7e8ee90845556a90faf8b043cbefd77b8903
author Jorge Lopez <jorge.lopez2@hp.com> 1654723763 -0500
committer Hans de Goede <hdegoede@redhat.com> 1655037595 +0200

platform/x86: hp-wmi: Resolve WMI query failures on some devices

WMI queries fail on some devices where the ACPI method HWMC
unconditionally attempts to create Fields beyond the buffer
if the buffer is too small, this breaks essential features
such as power profiles:

         CreateByteField (Arg1, 0x10, D008)
         CreateByteField (Arg1, 0x11, D009)
         CreateByteField (Arg1, 0x12, D010)
         CreateDWordField (Arg1, 0x10, D032)
         CreateField (Arg1, 0x80, 0x0400, D128)

In cases where args->data had zero length, ACPI BIOS Error
(bug): AE_AML_BUFFER_LIMIT, Field [D008] at bit
offset/length 128/8 exceeds size of target Buffer (128 bits)
(20211217/dsopcode-198) was obtained.

ACPI BIOS Error (bug): AE_AML_BUFFER_LIMIT, Field [D009] at bit
offset/length 136/8 exceeds size of target Buffer (136bits)
(20211217/dsopcode-198)

The original code created a buffer size of 128 bytes regardless if
the WMI call required a smaller buffer or not.  This particular
behavior occurs in older BIOS and reproduced in OMEN laptops.  Newer
BIOS handles buffer sizes properly and meets the latest specification
requirements.  This is the reason why testing with a dynamically
allocated buffer did not uncover any failures with the test systems at
hand.

This patch was tested on several OMEN, Elite, and Zbooks.  It was
confirmed the patch resolves HPWMI_FAN GET/SET calls in an OMEN
Laptop 15-ek0xxx.  No problems were reported when testing on several Elite
and Zbooks notebooks.

Fixes: 4b4967cbd268 ("platform/x86: hp-wmi: Changing bios_args.data to be dynamically allocated")
Signed-off-by: Jorge Lopez <jorge.lopez2@hp.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220608212923.8585-2-jorge.lopez2@hp.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>