Linux 固件
Linux 固件是与 Linux 内核一起发行的软件包，它包含了某些硬件设备部分或全部功能所需固件的二进制 blob 。 因为一些硬件制造商不开放构建固件的源代码，所以这些二进制 blob 一般来说是专有 blob。
现在的超威半导体和英伟达显卡一般都需要二进制 blob 才能正确的加载硬件。
Starting at Broxton (a Skylake-based micro-architecture) Intel CPUs require binary blobs for additional low-power idle states (DMC), graphics workload scheduling on the various graphics parallel engines (GuC), and offloading some media functions from the CPU to GPU (HuC).[1]
此外，现在的英特尔 Wi-Fi 芯片组大多都需要 blob。[2]
安装
出于安全原因，要避免在运行中的内核热加载固件。现代的 init 系统，比如说
systemd 强烈反对从用户空间加载固件。
内核
A few kernel options are important to consider when building in firmware support for certain devices in the Linux kernel:
Including firmware files into binary kernel images that are not available under the terms of the GPL, may result in a violation of the GPL if the image is distributed. It is wise to consult a lawyer before distributing images that contain firmware files from sys-kernel/linux-firmware.
Kernels prior to v4.18
For kernels released prior to version 4.18:
- CONFIG_FIRMWARE_IN_KERNEL (DEPRECATED)
- Note this option has been removed as of versions v4.16 and above.[3] Enabling this option was previously necessary to build each required firmware blob specified by EXTRA_FIRMWARE into the kernel directly, where the
request_firmware()function will find them without having to make a call out to userspace. On older kernels, it is necessary to enable it.
Device Drivers --->
Generic Driver Options --->
-*- Userspace firmware loading support
[*] Include in-kernel firmware blobs in kernel binary
(/lib/firmware) Firmware blobs root directory
Kernels v4.18 and higher
For kernels beginning with 4.18:
- Firmware loading facility ( CONFIG_FW_LOADER )
- This option is provided for the case where none of the in-tree modules require userspace firmware loading support, but a module built out-of-tree does.
- Build named firmware blobs into the kernel binary ( CONFIG_EXTRA_FIRMWARE )
- This option is a string and takes the (space-separated) names of firmware files to be built into the kernel. These files will then be accessible to the kernel at runtime.
Device Drivers --->
Generic Driver Options --->
Firmware loader --->
-*- Firmware loading facility
() Build named firmware blobs into the kernel binary
(/lib/firmware) Firmware blobs root directory
USE 标记
USE flags for sys-kernel/linux-firmware Linux firmware files
compress-xz
|
Compress firmware using xz (app-arch/xz-utils) before installation |
compress-zstd
|
Compress firmware using zstd (app-arch/zstd) before installation |
initramfs
|
Create and install initramfs for early microcode loading in /boot (only AMD for now) |
redistributable
|
Install also non-free (but redistributable) firmware files |
savedconfig
|
Allows individual selection of firmware files |
unknown-license
|
Install firmware files whose license is unknown |
Emerge
root #emerge --ask sys-kernel/linux-firmware可选：Savedconfig
After emerging sys-kernel/linux-firmware, the configuration file is made into /etc/portage/savedconfig/sys-kernel/linux-firmware-ddmmyyyy. This file can be edited and the unwanted lines be commented out or deleted. Edit and save the file and re-emerge sys-kernel/linux-firmware with the savedconfig USE flag:
root #echo sys-kernel/linux-firmware savedconfig >> /etc/portage/package.use/kernelroot #emerge --ask sys-kernel/linux-firmware可选：压缩
Firmware to be loaded into the kernel can be compressed in order to achieve greater space efficiency and faster read speeds (at the expense of processing time). See the CONFIG_FW_LOADER_COMPRESS kernel symbol for additional information.
xz compression is supported via the CONFIG_FW_LOADER_COMPRESS_XZ symbol. Note that only none or crc32 integrity check types (by passing -C crc32 option to the xz command) are supported.
As of kernel version 5.19, zstd compression is supported via the CONFIG_FW_LOADER_COMPRESS_ZSTD symbol.[4]
故障排除
Searching for loaded firmware
dmesg can be grepped to determine what firmware has been loaded:
user $dmesg | grep -i firmware移除
Unmerge
root #emerge --ask --depclean --verbose sys-kernel/linux-firmware另请参阅
- Fwupd — a daemon that provides a safe, reliable way of applying firmware updates on Linux.
- Kernel — 操作系统的核心。
- Iwlwifi — Intel's current wireless chips的无线驱动
- Microcode — describes various ways to update a CPU's microcode in Gentoo.
- AMDGPU — the next generation family of open source graphics drivers using the new Display Core (DC) framework for Vega GPUs and Raven Ridge APUs. It is however also capable of handling newer AMD/ATI Radeon graphics cards based on GCN1.0+, namely the Southern Islands, Sea Islands, Volcanic Islands, and Arctic Islands chipsets.
- Intel — the open source graphics driver for Intel GMA on-board graphics cards and Intel Arc dedicated graphics cards, starting with the Intel 810.