https://bugzilla.kernel.org/show_bug.cgi?id=215003 --- Comment #5 from Lukas Wunner (lukas@xxxxxxxxx) --- Hm, why are runtime services disabled? Are you using "noefi" or "efi=noruntime" on the command line or is this perhaps an RT kernel? Could you attach full dmesg output? Looking at the ACPI dump I notice that GMUX only has an 8 byte Memory32Fixed region: Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings { Memory32Fixed (ReadWrite, 0xFE0B0200, // Address Base 0x00000008, // Address Length ) }) On my pre-retina MacBookPro9,1 it's a 256 byte Decode16 region: Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings { IO (Decode16, 0x0700, // Range Minimum 0x07FF, // Range Maximum 0x01, // Alignment 0xFF, // Length ) }) Apple already changed the I/O interface once when they switched to retina displays in 2012: Before, registers where accessed directly. After, registers where accessed through a mailbox interface which required 3 32-bit registers for communication. It looks like they changed the interface again, however now there's only a memory region with 8 bytes, so only 2 32-bit registers. It will be necessary to reverse-engineer the new interface (again) to get support for GMUX working on these newer machines. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
