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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 20 Jan 2020 23:55:43 +0200
Message-ID: <CAHp75Veb02m3tU9tzZe912ZmX5mdaYkZ90DD67FVERJS15VsXw@mail.gmail.com>
Subject: Re: [PATCH v1 2/2] firmware: dmi_scan: Pass dmi_entry_point to
 kexec'ed kernel
To:     Jean Delvare <jdelvare@suse.de>
Cc:     "Eric W. Biederman" <ebiederm@xmission.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Dave Young <dyoung@redhat.com>,
        linux-efi <linux-efi@vger.kernel.org>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        kexec@lists.infradead.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mika Westerberg <mika.westerberg@linux.intel.com>
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On Mon, Jan 20, 2020 at 11:44 PM Jean Delvare <jdelvare@suse.de> wrote:
>
> On Mon, 20 Jan 2020 10:04:04 -0600, Eric W. Biederman wrote:
> > Second.  I looked at your test results and they don't directly make
> > sense.  dmidecode bypasses the kernel completely or it did last time
> > I looked so I don't know why you would be using that to test if
> > something in the kernel is working.
>
> That must have been long ago. A recent version of dmidecode (>= 3.0)
> running on a recent kernel
> (>= d7f96f97c4031fa4ffdb7801f9aae23e96170a6f, v4.2) will read the DMI
> data from /sys/firmware/dmi/tables, so it is very much relying on the
> kernel doing the right thing. If not, it will still try to fallback to
> reading from /dev/mem directly on certain architectures. You can force
> that old method with --no-sysfs.
>
> Hope that helps,

I don't understand how it possible can help for in-kernel code, like
DMI quirks in a drivers.

-- 
With Best Regards,
Andy Shevchenko