acpi: Add Darwin OSI support for Apple Mac hardware
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Authored by guest-seuros on Sun, Jan 18, 8:39 AM.

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Reviewers

adrian
imp
jkim
obiwac
ngie

Summary

Apple Mac systems with dual GPUs (Intel iGPU + AMD/NVIDIA dGPU) hide the Intel integrated GPU when the ACPI firmware does not see _OSI("Darwin").

Linux handles this in drivers/acpi/osi.c by detecting Apple hardware via DMI, disabling all Windows OSI strings, and installing Darwin OSI.
Users can override with acpi_osi=!Darwin to restore Windows-like behavior.

Without this change FreeBSD always use the heavy duty GPU.
It fine in practice but impact the battery life seriously when laptop is not powered.

Apple hardware hide second GPU (Intel) from being listed.

Please note that some other laptops with dual GPU do suffer the same power consumption.

Test Plan

pciconf -lv | grep -A4 "class=0x0300"
Verify both GPUs visible
Check dmesg for "Apple hardware: enabled Darwin OSI" <<-- should i wrap the message in debug ?
Test disable: set hw.acpi.apple_darwin_osi=0 in loader.conf, reboot
Verify Intel GPU hidden again

vgapci1@pci0:0:2:0 │ Intel Crystal Well (Iris Pro 5200)
vgapci0@pci0:1:0:0 │ AMD Venus XT (R9 M370X)

Note (I did not try this with NVIDIA based Apple, those are older)

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Event Timeline

guest-seuros requested review of this revision.Sun, Jan 18, 8:39 AM

guest-seuros created this revision.

adrian added reviewers: imp, jkim, obiwac.Mon, Jan 19, 1:27 AM

adrian added a reviewer: ngie.Mon, Jan 19, 1:29 AM

jrtc27 subscribed.Mon, Jan 19, 3:33 AM

jrtc27 added inline comments.

sys/dev/acpica/acpi.c
4846	Why's only this one guarded by bootverbose? If anything isn't the error more important to show?

guest-seuros added inline comments.Tue, Jan 20, 9:20 AM

sys/dev/acpica/acpi.c
4846	The success message document an intentional ACPI policy override. The failure path is diagnostic-only, so it is appropriately gated by bootverbose to avoid user-facing noise. I tested this on many Apple systems ranging from 2011 to 2019. While it behaves correctly on those platforms, older or less common models (pre 2011) may expose ACPICA edge cases, which is why the failure path is keept for debuging. (i will get few of those machines soon to test). If this code proves to be stable across every range of Apple hardware and ACPICA versions, the failure branch itself could potentially and the logging be removed in the future.

looks good!

which function are you adding this to, acpi_reset_interfaces? phab says context not available and the line numbers don't seem to match up.

sys/dev/acpica/acpi.c
4839	nit but: wouldn't you want to want to warn if removing the window vendor strings failed too, if you think adding the Darwin vendor string failing is likely enough to warrant a warning message?

This revision is now accepted and ready to land.Tue, Jan 20, 11:57 AM

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sys/

dev/

acpica/

acpi.c

54 line(s)

Diff 169986

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