[Docs] Clarification of DVMT stolen calculation

[1alessandro1]

Today I've successfully managed to unlock the following hidden options with setup_var:

• CFG Lock set to 0x00 with the command: setup_var 0x4A3 0x00
  

• DVMT Total Gfx Mem set to MAX with the command: setup_var 0x234 0x03
  

My question arises when I try to unlock DVMT Pre-Allocated (I'm using a 4K display, so 128MB of preallocated required) with the command:

setup_var 0x233 0x04

Having checked the Bios offset beforehand:

And the result is the following:

Which corresponds to:

#define GRUB_EFI_SECURITY_VIOLATION GRUB_EFI_ERROR_CODE (26)

I've even tried other values and other setup_var2, setup_var_3 etc but unfortunately the result is the same. So I've checked WhateverGreen manual, to see how I would add the missing MBs from 32MB of pre allocated all the way to 128MB, but it wasn't clear to me, since this is an hybrid situation, where only Pre-Allocated cannot be modified - what is necessary to add apart framebuffer-patch-enable

Should I need only more framebuffer-fbmem set to (128-32)=96MB missing for the 4K display (the 32MB are already provided by the BIOS by default) hence increasing the hypotetical DVMT Pre-Allocated value to 128MB?

Here's the dump for easy access, thanks for your time.

ID: 0D220003, STOLEN: 32 MB, FBMEM: 19 MB, VRAM: 1536 MB, Flags: 0x00000402
TOTAL STOLEN: 52 MB, TOTAL CURSOR: 1 MB (1572864 bytes), MAX STOLEN: 116 MB, MAX OVERALL: 117 MB (123219968 bytes)
Camellia: CamelliaDisabled (0), Freq: 5273 Hz, FreqMax: 5273 Hz
Mobile: 0, PipeCount: 3, PortCount: 3, FBMemoryCount: 3
[1] busId: 0x05, pipe: 9, type: 0x00000400, flags: 0x00000087 - ConnectorDP
[2] busId: 0x04, pipe: 10, type: 0x00000400, flags: 0x00000087 - ConnectorDP
[3] busId: 0x06, pipe: 8, type: 0x00000400, flags: 0x00000011 - ConnectorDP
01050900 00040000 87000000
02040A00 00040000 87000000
03060800 00040000 11000000

[vit9696]

You cannot add "missing" memory in WEG. At most you can force the framebuffer to use less memory, this is what these options are about. And it will either fail or work unstable (or more or less ok). It is weird that you cannot change the option via setup_var while you can do that to e.g. CFG Lock. Maybe there is a bug in grub shell or your actions, but it is out of our scope.

[1alessandro1]

Thanks for these clarifications, indeed none of those patches are in the config.plist now

The system successfully boots macOS recovery (11.2.3) without panics, so I guess the 32MB value is fine, and matches the STOLEN: 32MB found in the dumps. But the resolution is not 3840x2160, (in Debian Linux 4K works) - does WeG have something for 4K screens (like enable-hdmi20) which works for DP to DP connections?

[vit9696]

That most likely means the value is not enough. The only thing that exists is https://github.com/acidanthera/WhateverGreen/blob/master/Manual/FAQ.IntelHD.en.md#hdmi-in-uhd-resolution-with-60fps.

CC @lvs1974 @al3xtjames @usr-sse2 @0xFireWolf

[1alessandro1]

igfxonlnfbs=MASK boot argument (force-online-framebuffers device property) to specify indices of connectors for which online status is enforced. Format is similar to igfxfcmsfbs.

Little doubt here ^
If I have to specify force-online only for the connector (HDMI 00080000) highlighted:

Should I specify force-online-framebuffers (DATA) = 02 or 01? (Should I include 0 when counting or not?)

[vit9696]

Should be 01 I believe. Counts from 00.

[gatorback]

It took me five months to discover that DVMT settings were preventing 4K resolution. Lessons learned include:

• Use the terminal / tool: modgrubshell.efi
• Use the command: setup_var_cv

For more details see: https://www.tonymacx86.com/threads/how-to-configure-4k-resolution-for-an-optiplex-3090-mff.321968/post-2364717