[Bug 212985] ideapad_acpi: VPC2004:00: DYTC interface is not available. platform_profile interface is unavailable

[bugzilla-daemon@bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=212985

--- Comment #4 from Barnabás Pőcze (pobrn@protonmail.com) ---
> If I'm understanding correctly, you're saying to check the disassembled ACPI
> tables, right?

Yes, exactly.

From this part:


            Method (DYTC, 1, Serialized)
            {
                ITSV = Zero
                ITSM = Zero
                Local0 = Zero
                Local1 = (Arg0 & 0x01FF)
                Local2 = (Arg0 & 0xFFFFFE00)
                Switch (Local1)
                {
                    Case (Zero)
                    {
                        If (!Local2)
                        {
                            Local0 |= One
                            Local0 |= 0x0100
                            Local0 |= Zero
                            Local0 |= 0x40000000
                        }
                        Else
                        {
                            Local0 |= Zero
                            Local0 |= 0x04
                        }
                    }


it **seems to me** that only DYTC v4 is supported on that model - although I'm
not sure. The ideapad_acpi driver will only expose the platform_profile
functionality if it finds DYTC v5 or newer. The code was adapted from the
thinkpad_acpi driver, and the platform_profile support was contributed to that
driver by Lenovo employee Mark Pearson. I cannot remember the exact reason why
earlier versions are not supported, you could possibly write to the PDx86
mailing list (platform-driver-x86 at vger.kernel.org) and CC him if you want to
know more; or search back on lore.kernel.org.

-- 
You may reply to this email to add a comment.

You are receiving this mail because:
You are the assignee for the bug.