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Date:   Mon, 28 Feb 2022 17:33:49 +0100 (CET)
From:   Jiri Kosina <jikos@kernel.org>
To:     Greg KH <gregkh@linuxfoundation.org>
cc:     Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
        Dave Marchevsky <davemarchevsky@fb.com>,
        Joe Stringer <joe@cilium.io>,
        Tero Kristo <tero.kristo@linux.intel.com>,
        lkml <linux-kernel@vger.kernel.org>,
        "open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
        netdev@vger.kernel.org, bpf@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Peter Hutterer <peter.hutterer@redhat.com>
Subject: Re: [PATCH bpf-next v1 0/6] Introduce eBPF support for HID devices
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On Fri, 25 Feb 2022, Greg KH wrote:

> > I mean that if you need a bpf program to be loaded from userspace at
> > boot to make your keyboard functional, then you need to have the root
> > partition mounted (or put the program in the initrd) so udev can load
> > it. Now if your keyboard is supposed to give the password used to
> > decrypt your root partition but you need a bpf program on that said
> > partition to make it functional, you are screwed :)
> 
> True, but that's why the HID boot protocol was designed for keyboards
> and mice, so that they "always" work.  Yeah, I know many devices ignore
> it, oh well...

That's a very mild statement :)

*Most* of the recent modern HW doesn't support it as far as I can say.

Thanks,

-- 
Jiri Kosina
SUSE Labs