I have been struggling with this weird issue since last 15-20 days..!
Now I think I have narrowed down the error..
Dell Inspiron 7720 Laptop
Intel 3rd Gen Core i7 3630QM
Intel HM77 7 series chipset
Intel HD4000 + nVidia GT650M DDR5 2 GB optimus (Never works, I know)
Using Clover UEFI Bootloader on UEFI system
I have a DSDT for my laptop. But have tried with and without it too.
The Intel HD4000 works with QE/QC for a couple of times after fresh install. Then suddenly it stops working, although it is detected as usual. AGPM Capri and HD4000 kexts are loaded still I get no QE/QC... AGPM says "Unknown Platform"... I used a LegacyAGPM.kext to get around with that.
Now when the QE/QC is broken, I reboot the computer and in Clover deselect "GeneratePStates" and "GenerateCStates".... QE/QC is back!!! Again after couple of reboots, it is broken!!!
Now again i select "GeneratePStates" and "GenerateCStates", QE/QC starts working for few reboots!
What is my problem???