Does Apple load microcode for the IGPU?

Someone asked me if I knew if Apple loads Graphics micro code (Guc) for the IGPU and I can confirm that. Yes it does. Take a look at the following log data from my Apple MacBookPro13,3:

kernel: (AppleIntelSKLGraphics) [IGPU] Will fallback to host-side scheduling if graphics firmware fails to load
kernel: (AppleIntelSKLGraphics) [IGPU] Chose to use graphics firmware based on platform
kernel: (AppleIntelSKLGraphics) [IGPU] Graphics accelerator is using scheduler interface revision 3: Apple Firmware
kernel: (AppleIntelSKLGraphics) [IGPU] Scheduler: Multiple channel indexes per command streamer
kernel: (AppleIntelSKLGraphics) [IGPU] Scheduler: Process CSB using HWS.
kernel: (AppleIntelSKLGraphics) [IGPU] Scheduler: PM notify enabled
kernel: (AppleIntelSKLGraphics) [IGPU] Graphics Address: PPGTT, Separate Address Space
kernel: (AppleIntelSKLGraphics) [IGPU] MultiForceWake Enabled: Using 3D Driver
kernel: (AppleIntelSKLGraphics) [IGPU] Begin GuC load process
kernel: (AppleIntelSKLGraphics) [IGPU] Begin GuC load process
kernel: (AppleIntelSKLGraphics) [IGPU] ForceWake Multithread = 0x20002
kernel: (AppleIntelSKLGraphics) [IGPU] ForceWake Multithread = 0x20002
kernel: (AppleIntelSKLGraphics) [IGPU] CONFIG0 (0xD00) = 0x80000000
kernel: (AppleIntelSKLGraphics) [IGPU] CONFIG0 (0xD00) = 0x80000000
kernel: (AppleIntelSKLGraphics) [IGPU] GT_THREAD_STATUS = 0x400b0000
kernel: (AppleIntelSKLGraphics) [IGPU] GT_THREAD_STATUS = 0x400b0000
kernel: (AppleIntelSKLGraphics) [IGPU] Doing retry #0
kernel: (AppleIntelSKLGraphics) [IGPU] Doing retry #0

Debugging sleep issues…

A lot of people are still facing sleep/wake related issues and I like to figure out why so please check:


1.) Is that number a zero or some other value?
2.) Do you have a property with the name: IOPMDeepIdleSupported?
3.) Do you have a property with the name: IOPMSystemSleepType?

If the answer for the first question is zero, then I would like to know if you are using a dGPU or IGPU only.

The second question can be solved by adding the following code to your ACPI tables:

Scope (\_SB)
    Method (LPS0, 0, NotSerialized)
        Store ("Method \\_SB._LPS0 Called", Debug)
        Return (One)

Scope (\_GPE)
    Method (LXEN, 0, NotSerialized)
        Store ("Method \\_GPE.LXEN Called", Debug)
        Return (One)

If the answer for the last question is yes, then what value is it, and what SMBIOS are you using? Please note that this specific property is not part of Yosemite. The value represents the lowest possible sleep state and is checked by the following kexts:


That should be enough reasons for you to want that property.

I also added the following code to my ACPI tables:

Scope (\)
   Name (SLTP, Zero)

   Method (_TTS, 1, NotSerialized)
       Store ("Method \\__TTS Called", Debug)
       Store (Arg0, SLTP)

This, with additional checks, is used by Apple to skip parts for the NVMe SSD (RP01/IOPP/SSD0@0), AirPort (RP09/IOPP/ARP@0) and camera (RP10@1D,1/IOPP/CMRA) devices


There are two interesting NVRAM properties:

#define kIOSleepWakeDebugKey        "Persistent-memory-note"
#define kIOEFIBootRomFailureKey     "wake-failure"

That has to be it for now. Maybe later more…


Ok. Jaybee asked (see comments) how he should validate the values. That is a good question. Let’s start with PMStatusCode. This should be 0x0 (success).

IOPMDeepIdleSupported. This should be there with a value of true.

IOPMSystemSleepType is the lowest possible sleep state and this is set to 7 on my MacBook Pro. This will also issue a sleep request for the iGPU.

Some people said that this property wasn’t there on their setup. For some not until after a sleep/wake cycle, and then it was set to 2.

I have yet to figure out how important this value is and if that can cause any trouble.


Here is the first data from the AppleIntelSKLGraphicsFramebuffer.kext binary that I like to share with you:

06 00 1B 19 00 00 00 00 91 09 08 00 00 00 00 00
01 01 01 01 00 00 60 02 00 00 00 00 00 00 00 60
6C 05 00 00 6C 05 00 00 00 00 00 00 00 00 00 00
00 00 08 00 02 00 00 00 98 04 00 00 FF 00 00 00
01 00 00 00 20 00 00 00 FF 00 00 00 01 00 00 00
20 00 00 00 FF 00 00 00 01 00 00 00 20 00 00 00
02 13 13 00 00 00 06 00 03 00 00 00 04 00 00 00
80 DF 17 10 00 00 00 00 78 05 00 00 D2 05 00 00
40 06 00 00 00 00 00 00 00 00 00 00 00 00 00 00
10 23 1B 00 00 00 00 00 60 24 1B 00 00 00 00 00
60 24 1B 00 00 00 00 00 01 00 00 00 08 00 00 00
00 00 00 00 00 00 00 00

The above example will activate/support only one display, and some of the data is well known by now so I am going to skip stuff like the black value, which is (still) the platformID.

Unused/disabled frame buffer data (see orange values) have also changed.

New are the red values, all represent a different kinds of version information.

New is the blue value, representing the number of Slices (Slice Count).

New is the green value, representing the number of Execution Unit (EU Count).

The purple data is used for the TCON configuration and this is what I found in the log file of my MacBookPro13,3:

kernel: (AppleIntelSKLGraphicsFramebuffer) IG: TCON:
kernel: (AppleIntelSKLGraphicsFramebuffer) Aux not ready at HW
kernel: (AppleIntelSKLGraphicsFramebuffer) IG: TCON:
kernel: (AppleIntelSKLGraphicsFramebuffer) BAN_DPCD_0x0_EXPECTED failed, got deadbeef

See also:

AppleIntelFramebufferAzul.kext (Part I)
AppleIntelFramebufferAzul.kext (Part II)
AppleIntelFramebufferAzul.kext (Part III)

Black screen with movable cursor…

I received a couple of question this month and one of them jumps out; Stuck on a black screen with a movable cursor.

Ok. I think I know what you mean and this is my work around for it (mentioned before in one of my replies in a blog post):

1.) Press enter (background image flashes shortly).

2.) Enter you password (screen is still black).

3.) There is your desktop.

Well. That’s it. Works every time for me. No matter what display connector that I use (HDMI, DVI or VGA).

p.s. You may run into this black screen with movable cursor if your PC failed to wake up, after you’ve used the on/off switch to boot again.

Update: Apple change something in 10.12.3 Beta (16D30a) and as a result the screen is no longer black.

Booting without monitor (cable) attached…

I tried to boot my Skylake setup without a monitor (cable) attached and it failed, up until the moment that I connect the monitor cable. It didn’t even (try to) load the boot loader from the M2 SSD. What I noticed was a flashing cursor at the top left corner, and only then did it load the boot loader from the M2 SSD. This is a serious BIOS bug.

Three questions:

1.) Can you boot (your Skylake setup) without a monitor attached?

2.) If yes, is that with an NVIDIA (or AMD) dGPU or the IGPU?

3.) Do you happen to know a work around for this problem?

Edit: It boots up with the monitor cable attached, even if the monitor is switched off – the BIOS may want to read the EDID and use the power from the DVI cable.

Breaking news…

Tim Cook said that Apple is still committed to the Mac and specifically mentioned the desktop aka iMac. What does this mean for us? Well. I am sitting on a flight right now in the USA – with a couple of other people – and am listening to two people, talking about a new Apple keyboard… with an on-off switch.

Let’s see if this in flight Internet thing works… Ok. Cool. It actualy works.

Edit: the next iPad and iPhone is said to come with some form of wireless charging, and the iMac stand should support that, and work as a two way charger; burst mode for iPhone and iPad, and a slower (normal?) mode for the new keyboard and magic trackpad. They also talked about pairing the TouchID (read our fingerprint) with your Apple ID, so that you can use it anywhere in the world on all supported Mac’s. Though Apple is said to still investigate the legal and privacy implications of it.

Hardware support for TouchID is backed in on the motherboard, just like the new Macbook Pro, and the new keyboards will not work with current Mac models. It can also only power on/off the Mac that it is paired with.

The two people do not believe that the current Mac Pro will be sold in 2017; a new power desktop should replace it, or “the memo to employees” should stop Apple from exploring this path.

Apple is also working on a “Hub” to interact with smart devices in our homes, and it should also work as backup facility and WiFi access point.

It is four people (two are obvious developers) with Apple badges in one and the same plane. Sounds great, but let’s just see if anything actually ends up in our hands 😉


What are they chances that you ever get to meet Apple engineers in an airplane, or anywhere else for that matter, and then they also talk openly about unreleased products. Zero you say. And you are right!

So Pike are you saying that it never happened? Correct! I hereby retract my blog post. I’ll keep it up, but with this note:

We since learned that the people in this airplane were ex-Apple employees. People who started their own company, so that they could design and produce products for Apple customers. They have nothing to do with Apple.

Ok. There you have it. This is the note that I have to post here. Go figure!