I’m attempting to disable the ASM1083/ASM1085 PCIe to PCI Bridge on my ASUS P9D WS Motherboard via BIOS Mod on a NAS System running Debian Linux. Yes, I know this is Win-Raid, but I think it’s one of the biggest BIOS Mod Community out there, so I hope that you can help me nevertheless.
This seems to be needed because in Linux the ASPM Support is disabled as soon as this Controller is detected.
Indeed it works if I select MiniSetupResourceSection (mostly HEX readable) instead of the “Top-Level” Setup (which has mostly HEX jibberish).
So I should be able to just set the Parameter using
setup_var.efi 0x96=0x0
Which should disable PCIe Root Port #2 to which the ASM1083/1085 is connected.
Only problem is that this Motherboard (ASUS P9D WS) apparently sucks big Time: UEFI support is completely broken. I cannot get Linux to UEFI boot (Hard Drive UEFI is NOT even detected in BIOS/UEFI), cannot get EFI Shell on a USB Stick to boot, cannot get Clover to UEFI boot either. All I see is a black Screen with a “_” (Cursor) at the Top. Nothing happens from there.
Well, I am using the Integrated Intel iGPU. I mean, that was the whole Purpose of this Motherboard (cheap Xeon Platform supporting ECC Memory and iGPU Transcoding for Frigate).
I’d assume other reasons, maybe a graphics card from that generation that has no EFI firmware?
So not sure what you mean. You mean I should try adding an external GPU and try with that ? I don’t think I have other PCIe Slots available anymore.
Well, firmware has what’s needed for EFI graphics (EFI driver and GOP):
Can you enter bios settings when booting in UEFI mode with CSM disabled?
Do you see a post screen when booting in UEFI mode with CSM disabled?
When do you see a “black Screen with a “_” (Cursor) at the Top”? After post is completed or does the machine note even boot through the power on self test (POST)?
The “_” was when I tried to boot a UEFI USB Flashdrive with Clover on it (and IIRC the same happened with Memtest86, but I’m not 100% sure anymore).
I have both UEFI + CSM enabled at the moment and I can enter BIOS without Issues.
Strangely though I CANNOT anymore use the Keyboard in e.g. GRUB Menu to select the Kernel I want. It’s like the USB Keyboard is completely frozen AFTER BIOS Screen (but it’s OK to enter BIOS). Go figure.
I didn’t try with CSM Disabled to be honest. Do you think that would make a difference ?
Right now I’m trying to compile a Custom Kernel which patches this stupid ASM1083/1085 Quirck. But it’s only for testing, far from an Ideal solution . Even patching the ACPI Tables was useless because PCI Autodiscovery forces ASPM to be turned off anyways …
That’s normally not a ‘go figure’, it’s depending on settings. You can disable firmware check for USB devices to boot more quickly, but that means that these devices are depending on OS driver support for being used. Only to recommend when really no typing is needed between end of post and before the OS is fully booted ( = having initialized all devices including keyboards and mice by the OS)
I don’t see bios or firmware problems here. You can see a GRUB screen in UEFI mode, so that’d mean the graphics system is basically working OK. Try with disabling CSM in addition. Avoid secure boot at least for the moment, that has other caveats with both Linux and Windows
Then that was after post and seems to be caused by an improperly configured boot device.
A simple USB Stick for EFI boot has FAT32 file system (MBR) and one folder with a subfolder which contains one file named bootx64.efi which should be a valid EFI shell or a valid EFI program (like ru.efi) or the windows bootmanager.
Pretty sure I already enabled all Legacy USB Support.
I can see a GRUB Screen in CSM Mode. As I said, I NEVER EVER managed to get UEFI Boot to work. I also tried on the HDD but whereas on the USB it manages to find it’s UEFI Enabled when trying to select Boot Overrides from “Setup”, on the HDD it cannot find it at all and doesn’t even show a “UEFI” Entry for it .
I had tried with the UEFI Shell from EDK2 Builds (a VERY old Image), but I think I also tried a more recent Image without success. Now the PC is in a corner without possibility of easily getting a Display attached to it though.
I cannot even find the USB Flashdrive I was using anymore. I tried FAT32 with the bootx64.efi in the ROOT Folder, EFI Subfolder, EFI\Boot Subfolder but nothing did anything unfortunately …
Your observations aren’t completely consistent, it’s from ‘USB stick stops at cursor’ to ‘Grub loaded’ which might have been kind of EFI boot, but you don’t know if CSM was disabled or not.
In addition just trying locations for bootx64.efi instead of using the one correct location adds a lot of variables to this game.
I’m sorry, but can’t help you from the distance with this! Good luck!
HDD CSM Boot works → I get to GRUB
HDD UEFI Boot is a non-starter → it does NOT even get listed as available Boot Drive in UEFI Mode under BIOS “Boot” Menu
USB UEFI Boot “starts” → I get to “_” on a Black Screen
Anyways, even with a Custom Built Kernel it doesn’t look like ASPM wants to work on this Damn Board.
I actually just tried with another USB Flashdrive.
Maybe changing some Settings about USB XHCI / EHCI also helped … unsure.
And I copied the bootx64.efi AND shellx64.efi both in /, /efi and /efi/boot (relative to the Root of the USB Flashdrive). Then I managed to get to the UEFI Shell.
It still kinda sucks because it freezes e.g. after copying one File. But it’s kind of OK for no write Activity .
That did unfortunately not solve the Problem I was looking to solve (maybe it cannot or maybe I have some other device that Prevents ASPM), but at least the EFI Shell kinda works .
Weird that it was this complicated to get it working though.
EDIT 1: this is probably still the “Old” TIANOCORE UEFI Shell from 2018 or so, but it works for now at least.
. Even patching the ACPI Tables was useless because PCI Autodiscovery forces ASPM to be turned off anyways …
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