Maxim Polyakov has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/32044 )
Change subject: {mb,soc/intel/skylake}: Update GFX devtree options ......................................................................
Patch Set 7:
Patch Set 6:
why set PrimaryDisplay for the Librems (and most other Google devices) to Auto (which was the previous default since not set by coreboot?), but set Chromebooks to iGFX (via the new enum default)?
I know that Chromebooks use only the internal graphics card. However, I’m not sure about Intel reference design boards in src/mb/intel. Are these Chromebooks too? I have never seen them.
I have Intel KBL-R RVP with i5-8350 soc. This mainboard doesn`t have a PEG port, but I can insert a GPU card into PCH PCIe x4 and it should work. However, if you use the value Primary_iGFX, then the external GPU won't be used for output (unless dynamic switching is active in OS). For this reason, for the reference design board it is better to use the automatic detection of the primary GPU (or use the Display_PCH_PCIe value, but I decided to use the Auto).
iGFX should be used only when the system uses a GPU inside soc and does not provide for connecting external devices.
I read about the Librem article https://www.pcworld.com/article/2849795/purism-librem-15-linux-laptop-blends... , which mentions external GPU: "The Librem 15 includes a 15.6-inch 1920x1080 display, an 8-core 2.3 GHz Intel Core i7 CPU, NVIDIA graphics..." But I didn`t find information about a discrete GPU in the coreboot for these laptops. Maybe it was not implemented. I will remove this parameter from the devicetree.cb to use the Primary_iGFX value for these notebooks.
Thanks