Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754531Ab0KKKEy (ORCPT ); Thu, 11 Nov 2010 05:04:54 -0500 Received: from metis.ext.pengutronix.de ([92.198.50.35]:33850 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754256Ab0KKKEw (ORCPT ); Thu, 11 Nov 2010 05:04:52 -0500 Message-ID: <4CDBBFB7.70806@pengutronix.de> Date: Thu, 11 Nov 2010 11:04:39 +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: Wolfgang Grandegger , "David S. Miller" , Wolfram Sang , Christian Pellegrin , Barry Song <21cnbao@gmail.com>, Samuel Ortiz , socketcan-core@lists.berlios.de, netdev@vger.kernel.org, LKML , andrew.chih.howe.khor@intel.com, qi.wang@intel.com, margie.foster@intel.com, yong.y.wang@intel.com, Masayuki Ohtake , kok.howg.ewe@intel.com, joel.clark@intel.com Subject: Re: [PATCH net-next-2.6 v2] can: Topcliff: PCH_CAN driver: Fix build warnings References: <005301cb7ffa$5b63cd90$66f8800a@maildom.okisemi.com> <00fe01cb8009$62e11410$66f8800a@maildom.okisemi.com> <4CD945B4.4060408@pengutronix.de> <002501cb8186$b56a6280$66f8800a@maildom.okisemi.com> In-Reply-To: <002501cb8186$b56a6280$66f8800a@maildom.okisemi.com> X-Enigmail-Version: 1.0.1 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigEAC1BD5DD8E5F0D1A31083FD" 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: 2101 Lines: 62 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigEAC1BD5DD8E5F0D1A31083FD Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: quoted-printable On 11/11/2010 10:56 AM, Tomoya MORINAGA wrote: >>>>> + if (priv->tx_obj =3D=3D (PCH_OBJ_NUM + 1)) { /* Point tail Obj + = 1 */ >>>>> + while (ioread32(&priv->regs->treq2) & 0xfc00) >>>>> + udelay(1); >>> >>> When points tail of Tx message object, >>> this driver waits until completion of all tx messaeg objects. >> >> Looping busy it not an option here. >> >>> Thus, application/driver ought not to be able to put Tx object exceed= the number of tx message object. >>> Thus I think these code(netif_stop_queue/netif_wake_queue) are comple= tely redundant. >> >> Nope - please remove the waiting completely and convert your flow >> control to netif_stop_queue/netif_wake_queue. >> >=20 > I see. > I will remove like above. >=20 > BTW, Let me know the reason. > Could you explain the reason why you deny looping busy loop ? That would kill performance. 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 | --------------enigEAC1BD5DD8E5F0D1A31083FD 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/ iEYEARECAAYFAkzbv7sACgkQjTAFq1RaXHMUsgCfU4InjhlY4IYTO5xwHD6wOOQk 12kAn291ha7SfRpl2bC5KWVJe8L+EQsH =jGR6 -----END PGP SIGNATURE----- --------------enigEAC1BD5DD8E5F0D1A31083FD-- -- 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/