Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753315Ab3JWLaI (ORCPT ); Wed, 23 Oct 2013 07:30:08 -0400 Received: from top.free-electrons.com ([176.31.233.9]:45544 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752629Ab3JWLaG (ORCPT ); Wed, 23 Oct 2013 07:30:06 -0400 Date: Wed, 23 Oct 2013 12:28:09 +0100 From: Maxime Ripard To: Fan Rong Cc: coosty@163.com, daniel.lezcano@linaro.org, linux@arm.linux.org.uk, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com, pawel.moll@arm.com, rob.herring@calxeda.com, linux-sunxi@googlegroups.com Subject: Re: [Add SMP support for Allwinner A20: PATCH V5 3/3] Add arch count timer node in dts for Allwinner A20(sunxi 7i). Message-ID: <20131023112809.GX3041@lukather> References: <1382027827-10080-1-git-send-email-cinifr@gmail.com> <1382027827-10080-4-git-send-email-cinifr@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="BjOm3tsK/2NdfZj2" Content-Disposition: inline In-Reply-To: <1382027827-10080-4-git-send-email-cinifr@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2483 Lines: 62 --BjOm3tsK/2NdfZj2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 18, 2013 at 12:37:07AM +0800, Fan Rong wrote: > Linux kernel usually use virtual arch timer for smp cpu tick. But the > arch timer register VCTOFF normally is very different between the two > cpus in A20 afer hardware reset, so SMP Cpus will see different time > tick. It will cause kernel crash currently. You have two choices to > fix it: 1 Simpley use physical arch timer, 2 Set VCTOFF to same value > for each cpu in bootloader. The first choice will cause some other > problem for kernel, especially for KVM, guest OS want to use virtual > arch timer. So the second choice is perfect. So if you want to use > arch timer for smp cpu tick, you must ensure you bootload have set > same VCTOFF for all cpus. >=20 Is your patchset working without that last patch? I'm not really wanting to apply it right now. It relies on a bootloader behaviour that is not implemented by any bootloader we have openly available right now. I will apply it after it's been merged in at least u-boot-sunxi. Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --BjOm3tsK/2NdfZj2 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJSZ7LJAAoJEBx+YmzsjxAgUsEP/j9Llb0DVBUwhFTgQ79KjwS1 64huiN/41x0sKn9UDwgUOzC02U/jOqmzE6Drh/bq4VYKSvNZUOb/Dpl08Em4emIn EBLAgLr03DwwA+qj0nCfTfTopV7C+UHhen21j01T7fhhglsJMKtgaDPYdkWCfuky v/7fJbfMM1nJmNLrlQInFQUtFHA7Hmb7GWf8RejhrDGnkDp2HaYHhCp5nzw36isv Yc2+ybkXX+MSlwuEwRaYQXSFGMt/E2gHdAlw4HaIrRS+tZBJuVH84YeUpKXWnMTP W0MgC6dUmSnyMlMkY/3oQPinHLPc2/MStO8TrqBngPGTdhjzNCya+YuVSiS/Iaih j+4dpLTB+3EVhRp2I9bJl/oW9Fa6GjWoLqnGlPQfWMZbTx7oLaTCW5/eCLxUPlYW Pes2Y4ZHMdZjEP+VGeDb7qJkepqsTkqfuY8PeUhhYYDveCxxqkbMLgVcNi3zn4zX TXzJW4Z6GosWy+34iwl649T7XLf3BJcyFxrZy/1ttfQXgR2MjRVnYj0jJgLCangN 0I1ihX2DBA1ukIgOqiJVvNfm2f7B7C/raOJJzoxkdWVD0t4SfOggw2vmtNSj2ME6 l6dAWw3KmK+Pf8g5mOhuQulYzmd/MGxEu2Vi605RXvj8RVB43SmW+Q5kx2AeMv8t p9PUvMnCdR7+goChnR3V =Mo3R -----END PGP SIGNATURE----- --BjOm3tsK/2NdfZj2-- -- 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/