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Go in the BIOS and switch it off? Certainly. Just one problem: Modern consumer BIOS interfaces are graphical and your GPU is off.
by tux3 1y ago
Go in the BIOS and switch it off?
Certainly. Just one problem: Modern consumer BIOS interfaces are graphical and your GPU is off.
- ThePowerOfFuet 1y agoThat's not how it works; Secure Boot kicks in once EFI hands over control.
- mjg59 1y agoThe driver that initialises your plug-in GPU is shipped in flash on the card, is signed by Microsoft, and won't run unless that signature validates.
- tsimionescu 1y agoDoesn't that happen only after UEFI starts the boot process, and only if Secure Boot is enabled?
- mjg59 1y agoI don't understand what "UEFI starts the boot process" means? The firmware is what initialises the hardware. If the code needed to initialise your GPU doesn't have a trusted signature then it won't be executed, and you won't have any working graphics, so you won't have a UI to let you disable secure boot. If secure boot isn't enabled in the first place then yes this isn't a problem.
- ThePowerOfFuet 1y agoI am reticent to argue with someone of your reputation, but AFAIK UEFI can initialize a basic framebuffer (and write to it) in a standardized manner without needing any ROM on the card. https://wiki.osdev.org/GOP https://wiki.osdev.org/GOP
- mjg59 1y agoThe GOP driver is provided by the card, and then exposes a standardised interface to the firmware.
- tux3 1y agoThe GPU is initialized earlier, so that the screen turns on. The GPU driver can access main memory through the bus. If you let arbitrary code run before you start checking, you don't have a secure boot chain.