Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754732AbcC1J2q (ORCPT ); Mon, 28 Mar 2016 05:28:46 -0400 Received: from mail.gw90.de ([188.40.100.199]:48683 "EHLO mail.gw90.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752037AbcC1J2n (ORCPT ); Mon, 28 Mar 2016 05:28:43 -0400 X-Greylist: delayed 2638 seconds by postgrey-1.27 at vger.kernel.org; Mon, 28 Mar 2016 05:28:43 EDT Message-ID: <1459154648.2351.19.camel@users.sourceforge.net> Subject: [REGRESSION] firmware: dmi_scan: add SBMIOS entry and DMI tables From: Paul Menzel To: Ivan Khoronzhuk , Jean Delvare Cc: Linux kernel mailing list , coreboot@coreboot.org Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-1hjr2w+c+AWHoM6rwVxG" Date: Mon, 28 Mar 2016 10:44:09 +0200 Mime-Version: 1.0 X-Mailer: Evolution 3.18.5.1-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2024 Lines: 68 --=-1hjr2w+c+AWHoM6rwVxG Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Dear Ivan, dear Jeann, There is an unwanted regression due to commit=C2=A0d7f96f97 (firmware: dmi_scan: add SBMIOS entry and DMI tables). Since Linux kernel 4.2 the utility `cbmem`, used to access information stored in memory, from the coreboot project [1] does not work anymore on a lot of systems as reported in coreboot=E2=80=99s issue tracker as tick= et #33 [2]. ``` Failed to mmap /dev/mem: Resource temporarily unavailable ``` Aaron Durbin analyzed on the coreboot mailing list [3]: > > 3) Why is that range set as uncached-minus?=C2=A0=C2=A0Would write-back= work? > > Please see this thread: > http://www.coreboot.org/pipermail/coreboot/2015-September/080381.html > > The actual issue stems from > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/dri= vers/firmware/dmi_scan.c?id=3Dd7f96f97c4031fa4ffdb7801f9aae23e96170a6f > which maintains a persistent mapping of smbios tables. It uses > dmi_remap() which is '#define dmi_remap ioremap' which is where the > uncached-minus PAT entry comes from. It should be using the same > mechanism as=C2=A0=C2=A0the ACPI table mappings which uses ioremap_cache(= ). It=E2=80=99d be great, if the commit could be reverted, or the code be chan= ged in a way that `cbmem` still works. If I should report this issue somewhere else, please tell me too, and I=E2=80=99ll do my best to follow up there. Thanks, Paul [1]=C2=A0https://www.coreboot.org [2]=C2=A0https://ticket.coreboot.org/issues/33 [3]=C2=A0https://www.coreboot.org/pipermail/coreboot/2015-October/080568.ht= ml --=-1hjr2w+c+AWHoM6rwVxG Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEABECAAYFAlb47tkACgkQPX1aK2wOHVglgwCcCNjnJw8yyYjJZiN+aF6iYGok gDQAnRU5eISNV1aWLdRjjsrBmi5TyTRx =q/Pi -----END PGP SIGNATURE----- --=-1hjr2w+c+AWHoM6rwVxG--