Indeed, this patch -- https://review.coreboot.org/c/coreboot/+/31448 ( src/device/pci: Add support for discrete VGA initialization and OpROM loading ) -- could help, because it will create the ACPI VFCT table for discrete RX 570 GPU instead of doing this for integrated HD 8670D. You could install it conveniently and securely with the help of csb_patcher.sh script ( http://dangerousprototypes.com/docs/Lenovo_G505S_hacking#NEWS or https://review.coreboot.org/c/coreboot/+/33509 ).
Although there will not be a VFCT for your integrated GPU, it should be working fine even without it, maybe at cost of a slightly higher power consumption. We have discovered that
" ACPI VFCT - it's a table where AMD stores the Radeon video BIOS when the system is booted up in UEFI mode." " Where the ACPI VFCT Table is missing, Power States may not work properly. "
so it seems without VFCT the integrated GPU is going to be at its' max TDP even while not loaded. For example, knowing that a total TDP of our G505S laptop's A10-5750M APU (CPU+GPU) does not exceed 35W and looking at the values for similar APUs at this table https://www.eteknix.com/amd-kaveri-a10-7850k-overclocking-analysis/7/ (all values except Intel / RAM / OC), approximately for our A10-5750M it should be
Idle | GPU load | CPU+GPU load 15.6W | 23.66W | 35W 44.5% | 67.6% | 100%
We already knew that A10-5750M is 15W at idle, but have learned that GPU adds approximately 23.66W - 15.6W = about 8W while at its' max TDP. This G505S laptop comes with a 65W PSU, so with iGPU at it max TDP -- the laptop's battery life will be smaller in about 65/(65-8) = 1.12 times. However I've never compared the consumption difference of coreboot vs UEFI, would be nice if someone could test it in practice.
Since this RX 570 discrete PCI-E card should have its' own flash chip for storing the AtomBIOS blob -- unlike our laptop's onboard discrete HD-8570M or R5-M230 -- I think in your case there should not be a need of storing the discrete GPU's AtomBIOS ROM at your coreboot BIOS in addition to the integrated one. However, if the advice above would not work, you could try extracting the discrete GPU's AtomBIOS , using either https://www.coreboot.org/VGA_support#How_to_retrieve_a_good_video_bios or https://github.com/g505s-opensource-researcher/g505s-atombios#description | https://mail.coreboot.org/pipermail/coreboot/2017-July/084660.html instruction.
Best regards, Mike
On Mon, Sep 9, 2019 at 10:04 PM awokd via coreboot coreboot@coreboot.org wrote:
Grzegorz Bogdał:
Thank you. I'll check it out and report sometime in September whether the patches helped my case.
Please note, AFAIK they have only been tested on G505s's, so may need some modification for your platform.
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