From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [patch 5/6] ps3: BD/DVD/CD-ROM Storage Driver Date: Fri, 13 Jul 2007 16:19:54 +0200 Message-ID: <200707131619.54898.arnd@arndb.de> References: <20070704132212.726923000@pademelon.sonytel.be> <1184335333.3402.20.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from moutng.kundenserver.de ([212.227.126.188]:56544 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761021AbXGMOiR convert rfc822-to-8bit (ORCPT ); Fri, 13 Jul 2007 10:38:17 -0400 In-Reply-To: <1184335333.3402.20.camel@localhost.localdomain> Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linuxppc-dev@ozlabs.org Cc: James Bottomley , Geert Uytterhoeven , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Alessandro Rubini , Paul Mackerras , Jens Axboe On Friday 13 July 2007, James Bottomley wrote: >=20 > > IC. > >=20 > > =A0 - flush_kernel_dcache_page() is a no-op on ppc64 > > =A0 =A0 (ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE is defined on parisc onl= y). > >=20 > > =A0 - For reference, drivers/scsi/ipr.c (another ppc64 driver) just= uses a plain > > =A0 =A0 kmap/memcpy/kunmap sequence > >=20 > > So what should I do? >=20 > Ask someone who knows the architecture ... Anton, Paulus or Benh ... = I'm > fairly certain PPC is VIPT and will need some kind of alias > resolution ... perhaps its associative enough not to let the aliases = be > a problem. I'm pretty sure that no ppc64 machine needs alias resolution in the ker= nel, although some are VIPT. Last time we discussed this, Segher explained i= t to me, but I don't remember which way Cell does it. IIRC, it automatica= lly flushes cache lines that are accessed through aliases. It's probably a good idea to have the flush_kernel_dcache_page() in the= re anyway, if only to serve as an example for people that copy it into architecture-independent drivers, same as what we do for the k{,un}map_atomic() that is also not required on ppc64. Arnd <>< - To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html