I've made some progress investigating 4k/60 via Haswell HD4600 IGPU on the Dell OptiPlex (SFF 7020) and posting my findings in hopes that it might give some leads to other more knowledgeable members of the community.
The main issue (as I understand it) moving from the working 4k setup on Catalina to Big Sur is the dependency on user space patches (specifically
enable-hdmi20
) which is presently broken in Lilu/WEG.
I'm testing on Catalina, but below are the values that I've been investigating/tweaking to remove the broken dependency. The values below are copied/tweaked from another user who has working 4k output on Big Sur on a mobile version of the HD4600 iGPU.
4k output is working on my main monitor with these settings (in Catalina) however:
Issues: potential unstable con0 values. con1 (second DP port, second monitor) wasn't working at all with this setup. When I power-cycled the second monitor my system crashed/rebooted.
I've added a column of my comments/findings for what I think the values do - I'm not at all an expert on this and many things might be incorrect.
!!!!!!! Folks are welcome to test/change/tweak values but please assume that this is highly
unstable. All properties go in the config.plist under DeviceProperties/ PciRoot(0x0)/Pci(0x2,0x0)
I hope this helps, and if anyone has any ideas/suggestions let me know!
Key |
Type |
Value |
Comments/findings |
AAPL,ig-platform-id |
Data |
0300220D |
Needed |
disable-external-gpu |
Data |
01000000 |
|
dpcd-max-link-rate |
Data |
14000000 |
Choose a DPCD maximum link rate for your display, where 4K=0x14 (default) or 1080p=0x0a. Related to driving 4k displays over display port (something to do with the link speed to the monitor?) |
enable-lspcon-support |
Data |
01000000 |
Enables DisplayPort to HDMI 2.0 output on some platforms with Intel IGPU (not sure if necessary) |
enable-max-pixel-clock-override |
Data |
01000000 |
Raises max pixel clock limit from 450 MHz (insufficient for 4k/60) to 675 MHz |
framebuffer-con0-alldata |
Data |
00000800 02000000 30000000 01050900 00040000 07010000 02040A00 00040000 07010000 |
These patch con0 (my main display port connection for primary monitor). I copied these values over directly from working mobile version. On my early testing in Catalina they *do* work to enable 4k on my primary DP port on my main monitor (con0). Values specific to the desktop version need to be found verified but I don't know how to find them.
Also, I haven't figured out how to enable second port/second monitor |
framebuffer-con-enable |
Data |
01000000 |
enable con patching |
framebuffer-fbmem |
Data |
00000003 |
|
framebuffer-patch-enable |
Data |
01000000 |
|
framebuffer-stolenmem |
Data |
00000004 |
|
framebuffer-unifiedmem |
Data |
00000080 |
|
hda-gfx |
String |
onboard-1 |
|