Linux Kernel：消失的firmware

今天想要使用4.14的Kernel源码编译kernel-firmware rpm包，结果发现编译失败了，经过简单的研究，发现Linux Kernel在4.14中把firmware删除了。

感兴趣的可以看相关修订邮件：http://lkml.iu.edu/hypermail/linux/kernel/1709.1/04650.html（为什么无法插入外链???）

这里截取一段邮件中的描述：

> Many many years ago (at the kernel summit in Boston), we all came to the

>agreement that the firmware/ tree should be dropped from the kernel, and

>everyone use the linux-firmware package instead. For some minor reason,

>David Woodhouse didn't send the pull request at that point in time, and

>everyone forgot about this.

>The topic came up in the hallway track at the Plumbers conference this

>week, so here's a single patch that drops the whole firmware tree. The

>last firmware update was back in 2013, and all distros have been using

>linux-firmware instead since at least that year, if not before. The

>only commits to that directory since 2013 was some kbuild fixups for

>various build tool issues.

>So lets finally drop this, we don't need to lug them around in the

>kernel source tree anymore, especially as no one wants or uses them.

>This has passed build testing with 0-day, I don't think it made it into

>linux-next this week, but I figured it was good to get in before

>4.14-rc1 was out.

这个补丁应用之后，引发了以下问题：

1.http://lkml.iu.edu/hypermail/linux/kernel/1709.2/00004.html

2. rpm包编译失败http://lkml.iu.edu/hypermail/linux/kernel/1709.2/00782.html

3. deb包编译失败http://lkml.iu.edu/hypermail/linux/kernel/1709.2/00717.html

解决了上述问题后，最终我们看到的结果是Linux Kernel从4.14开始就没有内置的firmware了，当然也不支持make firmware_install命令了，kernel-firmware的rpm包也不可能从Kernel sources中编译出来。回头我们再读最初的这封邮件，其中提到了kernel中的firmware自从2013年已经停止更新了，取而代之的是linux-firmware，并且几乎所有的发行版已经使用了linux-firmware取代了kernel-firmware。

看到这里，如果有心的话，可以去看看CentOS7中的firmware 包，你会发现kernel-firmware包消失了，替代者是linux-firmware。

所以，如果需要更新firmware，应该使用linux-firmware。这里提供2个简单的解决方案：

1. 可以去https://cbs.centos.org/koji/packageinfo?packageID=4127下载centos社区编译版；

2. 也可以使用https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git中的源码自行打包。