diff --git a/site/docs/install/dell3050.md b/site/docs/install/dell3050.md index 56008c9..e5f6e98 100644 --- a/site/docs/install/dell3050.md +++ b/site/docs/install/dell3050.md @@ -174,3 +174,44 @@ Observe the following photo of the flash (SOIC-8): You can otherwise flash internally, including from factory firmware(if the service jumper is set). + +Errata +====== + +TPM disabled +------------ + +The TPM is disabled on this device, to prevent hanging/boot delay in SeaBIOS, +due to buggy TPM drivers there. + +Legacy 8254 timer +----------------- + +Legacy 8254 timer enabled in coreboot, to prevent SeaBIOS from hanging. + +HyperThreading on 3050 Micro +-------------------------- + +Also called SMT. This is a feature where you get 2 threads on a single core. +It can improve performance in some workloads, but is actually a performance +liability in others, depending on your OS kernel/scheduler and the actual +workload. + +It is a security liability, due to the Spectre/Meltdown attacks, so we +recommend turning it off, at the very least from your running operating system. +On *this* platform, you can easily turn it off from coreboot. + +**Libreboot disables HyperThreading by default**, from Libreboot 20241206 rev8 +onward, on this board. To turn it back on, please [build from source](../build/) +and before running the build command, do this: + + ./mk -m coreboot t480_vfsp_16mb # replace t480 with t480s if needed + +In the menu that appears, go *Chipset -> Enable Hyperthreading* and turn it on. +Then exit from the menu, saving the config where prompted. You will see this +menu twice, because there are *two* configs for each of these boards. + +SMT is rarely of benefit in practise, but can be useful in some circumstances. +For example, if you're compiling a large codebase from source that takes hours, +SMT increases the building speed by about 15 percent; for example, a 3 hour +build job might take about 2 hours and 40 minutes instead. diff --git a/site/docs/install/t480.md b/site/docs/install/t480.md index f0cb737..48a8880 100644 --- a/site/docs/install/t480.md +++ b/site/docs/install/t480.md @@ -414,6 +414,44 @@ Errata Some features either don't work, or are untested, when running Libreboot on the ThinkPad T480 or T480s. +TPM disabled +------------ + +The TPM is disabled on this device, to prevent hanging/boot delay in SeaBIOS, +due to buggy TPM drivers there. + +Legacy 8254 timer +----------------- + +Legacy 8254 timer enabled in coreboot, to prevent SeaBIOS from hanging. + +HyperThreading on T480/T480s +---------------------- + +Also called SMT. This is a feature where you get 2 threads on a single core. +It can improve performance in some workloads, but is actually a performance +liability in others, depending on your OS kernel/scheduler and the actual +workload. + +It is a security liability, due to the Spectre/Meltdown attacks, so we +recommend turning it off, at the very least from your running operating system. +On *this* platform, you can easily turn it off from coreboot. + +**Libreboot disables HyperThreading by default**, from Libreboot 20241206 rev8 +onward, on this board. To turn it back on, please [build from source](../build/) +and before running the build command, do this: + + ./mk -m coreboot t480_vfsp_16mb # replace t480 with t480s if needed + +In the menu that appears, go *Chipset -> Enable Hyperthreading* and turn it on. +Then exit from the menu, saving the config where prompted. You will see this +menu twice, because there are *two* configs for each of these boards. + +SMT is rarely of benefit in practise, but can be useful in some circumstances. +For example, if you're compiling a large codebase from source that takes hours, +SMT increases the building speed by about 15 percent; for example, a 3 hour +build job might take about 2 hours and 40 minutes instead. + NFC support in T480 -------------------