Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753118AbaKJQbj (ORCPT ); Mon, 10 Nov 2014 11:31:39 -0500 Received: from mail-wg0-f49.google.com ([74.125.82.49]:44381 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751973AbaKJQbh (ORCPT ); Mon, 10 Nov 2014 11:31:37 -0500 From: Pali =?utf-8?q?Roh=C3=A1r?= To: Matt Fleming Subject: Re: [PATCH] rtc: Disable EFI rtc for x86 Date: Mon, 10 Nov 2014 17:23:46 +0100 User-Agent: KMail/1.13.7 (Linux/3.17.0-031700rc6-generic; KDE/4.14.1; x86_64; ; ) Cc: Borislav Petkov , Mark Salter , Alessandro Zummo , rtc-linux@googlegroups.com, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Dave Young , "H. Peter Anvin" , Matthew Garrett References: <1412339576-17972-1-git-send-email-matt@console-pimps.org> <20141109182231.GA29337@pd.tnic> <1415618533.14686.239.camel@mfleming-mobl1.ger.corp.intel.com> In-Reply-To: <1415618533.14686.239.camel@mfleming-mobl1.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart2674380.b8tmZvY1V1"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <201411101723.49197@pali> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --nextPart2674380.b8tmZvY1V1 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Monday 10 November 2014 12:22:13 Matt Fleming wrote: > On Sun, 2014-11-09 at 19:22 +0100, Borislav Petkov wrote: > > On Sun, Nov 09, 2014 at 06:37:46PM +0100, Pali Roh=C3=A1r wrote: > > > this patch totally disabled efi rfc driver on x86 machines > > > at compile time. But on some x86 machines it working > > > without crash and reading from file > > > /sys/class/rtc/rtc*/since_epoch returns correct > > > information. So why to disable compiling driver on > > > machines where driver working? > >=20 > > Sounds like we need an efi=3Drtc_enable knob for people who > > what to use it... >=20 > I'm not so sure. By and large, the EFI runtime Time services > just don't work very well on x86. Just because they work > sometimes, doesn't actually mean it's a good idea to use > them. >=20 > The one scenario where the time services are useful is early > on during boot when we want to get the timezone information. > I have vague recollections of someone working on that. On laptop Dell Latitude E6440 with 64bit kernel 3.17-rc6 (where=20 was rtc-efi.ko enabled at compile time for x86) it working fine=20 without crash. So I think that other Dell machines could work=20 too. Maybe problems which were reported are only specific for 32bit=20 UEFI? Or 32bit kernels? And I think that if I know that efi time service working on=20 machine, I should be able to use it with mainline kernel (without=20 hacking Kconfig to enable it and so...). =2D-=20 Pali Roh=C3=A1r pali.rohar@gmail.com --nextPart2674380.b8tmZvY1V1 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEABECAAYFAlRg5pUACgkQi/DJPQPkQ1IBZQCfTNuspzDzY56+NDmyAus3vY2g bqUAn0vAGETIMSXsu9RZoEq0myvGdJOW =MI7R -----END PGP SIGNATURE----- --nextPart2674380.b8tmZvY1V1-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/