Re: Dell BIOS issue reading Disk Extended data

From: Guilherme Piccoli <gpiccoli@canonical.com>
To: "K, Narendra" <Narendra.K@dell.com>
Cc: "Limonciello, Mario" <Mario.Limonciello@dell.com>,
	 "Barabash, Alexander" <Alexander.Barabash@dell.com>,
	"Engel, Amit" <Amit.Engel@dell.com>,
	"Guilherme G. Piccoli" <kernel@gpiccoli.net>,
	"halves@canonical.com" <halves@canonical.com>,
	 Jay Vosburgh <jay.vosburgh@canonical.com>,
	Dan Streetman <ddstreet@canonical.com>,
	 Gavin Guo <gavin.guo@canonical.com>,
	"x86@kernel.org" <x86@kernel.org>,
	 "grub-devel@gnu.org" <grub-devel@gnu.org>
Subject: Re: Dell BIOS issue reading Disk Extended data
Date: Wed, 31 Mar 2021 11:43:44 -0300	[thread overview]
Message-ID: <CAHD1Q_wtOh-+4EYZ7MzOS_sW16k+QhuG04nan5duJsdo-0s0tg@mail.gmail.com> (raw)
In-Reply-To: <BYAPR19MB47111EEF68658E9E3B1AFED1817D9@BYAPR19MB4711.namprd19.prod.outlook.com>

On Tue, Mar 30, 2021 at 2:43 PM K, Narendra <Narendra.K@dell.com> wrote:
> > On Fri, Jan 22, 2021 at 3:41 PM Limonciello, Mario
> > <Mario.Limonciello@dell.com> wrote:
> > >
> > > >
> > > > Hello Dell folks, I'm Guilherme Piccoli from Canonical - first of
> > > > all, apologies for the out-of-nowhere communication. We've been
> > > > investigating an issue that seems to date long time ago, and
> > > > eventually we could narrow it to what appears to be a Dell BIOS bug.
> > > > Notice I'm also looping a kernel x86 ML and grub-devel, just for the
> > > > purpose of archiving such discussion in public lists, to help others
> > > > that may find such an issue in the future.
> > > >
> > > > Since I don't have contacts of Dell representatives, I've just
> > > > raised a list of people from Dell contributing to kernel in the last
> > > > 2 years - maybe one of you could point me towards the path of a
> > > > proper contact/channel to discuss such an issue. If not, I'm sorry for the
> > noise.
> > > > Let me detail the problem we're observing - notice all of this is
> > > > about legacy BIOS mode, not UEFI.
> > >
> > > Most of the guys you CC'ed from Dell work on client related things,
> > > not servers.  So I'll move some of the client guys off of this thread into BCC.
> > > @K, Narendra can you please raise this with the appropriate team?
> > >
> >
> > Thanks Mario and K, Narendra - do we have any news about that?
> > Cheers,
>
> Hi Guilherme,
>
> Sorry for the delay in responding.
>

No problem Narendra K, thanks for your response!

> I checked with the team about the findings shared in this thread. Please find the details -
>
> The behavior seems to be working as designed. Legacy BIOS Option ROM implements logical block addressing support only up to 2TB.
> The option ROM will respond with 2TB as the size when queried by INT13h function 48h. For booting from volumes > 2TB, UEFI is needed.

So, just confirming, Dell doesn't support > 2TB offsets even using the
extended 64-bit offset from service 48h? I just want to confirm that
is a support limitation from Dell, I've tested another vendor and that
works in their machine, I could address > 2TB devices.

In case this is unsupported by Dell, do you have an official
documentation I can refer, to our customer?
Thanks again,

Guilherme