Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751612Ab0KVI2H (ORCPT ); Mon, 22 Nov 2010 03:28:07 -0500 Received: from metis.ext.pengutronix.de ([92.198.50.35]:56310 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751219Ab0KVI2G (ORCPT ); Mon, 22 Nov 2010 03:28:06 -0500 Message-ID: <4CEA2986.4080607@pengutronix.de> Date: Mon, 22 Nov 2010 09:27:50 +0100 From: Marc Kleine-Budde Organization: Pengutronix User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Thunderbird/3.0.10 MIME-Version: 1.0 To: Tomoya MORINAGA CC: andrew.chih.howe.khor@intel.com, socketcan-core@lists.berlios.de, Samuel Ortiz , margie.foster@intel.com, netdev@vger.kernel.org, Christian Pellegrin , linux-kernel@vger.kernel.org, yong.y.wang@intel.com, Masayuki Ohtake , kok.howg.ewe@intel.com, joel.clark@intel.com, "David S. Miller" , Wolfgang Grandegger , qi.wang@intel.com Subject: Re: [PATCH net-next-2.6 v3] can: Topcliff: PCH_CAN driver: Add Flow control, References: <4CE2434B.5050701@dsn.okisemi.com> <4CE27796.2000206@pengutronix.de> <007401cb87b1$a773b3d0$66f8800a@maildom.okisemi.com> <4CE64167.2030405@pengutronix.de> <003201cb8a02$f05b15e0$66f8800a@maildom.okisemi.com> In-Reply-To: <003201cb8a02$f05b15e0$66f8800a@maildom.okisemi.com> X-Enigmail-Version: 1.0.1 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig6AB79154414CF0941E795E6A" X-SA-Exim-Connect-IP: 2001:6f8:1178:4:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2096 Lines: 54 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig6AB79154414CF0941E795E6A Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 11/22/2010 06:05 AM, Tomoya MORINAGA wrote: > On Friday, November 19, 2010 6:20 PM, Marc Kleine-Budde wrote : >=20 >>>>> - spin_unlock_irqrestore(&priv->msgif_reg_lock, flags); >>>>> + pch_can_rw_msg_obj(&priv->regs->ifregs[1].creq, tx_obj_no); >>>> Still we have the busy waiting in the TX path. Maybe you can move th= e >>>> waiting before accessing the if[1] and remove the busy waiting here.= >>> I can't understand your saying. >>> For transmitting data, calling pch_can_rw_msg_obj is mandatory. >> Yes, but the busy wait is not needed. It should be enough to do the >> busy-waiting _before_ accessing the if[1]. >=20 > Do you mean we should create other pch_can_rw_msg_obj which doesn't hav= e busy wait ? ACK, and this non busy waiting is use in the TX path. But you add a busy wait only function before accessing the if[1] in the TX path. cheers, Marc --=20 Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de | --------------enig6AB79154414CF0941E795E6A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkzqKYoACgkQjTAFq1RaXHOeXQCfT7VKvE6KPYvx51UzDh+mMJzd hD8An2psKQO3bRnvocjSPOu3zAqs8Blw =4RUa -----END PGP SIGNATURE----- --------------enig6AB79154414CF0941E795E6A-- -- 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/