From mboxrd@z Thu Jan 1 00:00:00 1970 From: "erich" Subject: Re: Areca RAID driver remaining items? Date: Fri, 24 Feb 2006 10:08:22 +0800 Message-ID: <004701c638e7$31d9dc80$b100a8c0@erich2003> References: <1140458552.3495.26.camel@mentorng.gurulabs.com> <20060220182045.GA1634@infradead.org> <001401c63779$12e49aa0$b100a8c0@erich2003> <20060222145733.GC16269@infradead.org> <00dc01c63842$381f9a30$b100a8c0@erich2003> <1140683157.2972.6.camel@laptopd505.fenrus.org> <001901c6385e$9aee7d40$b100a8c0@erich2003> <1140688569.4672.24.camel@laptopd505.fenrus.org> <005a01c6386f$84b30d50$b100a8c0@erich2003> <1140696452.4672.43.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset="big5"; reply-type=original Content-Transfer-Encoding: 7bit Return-path: Received: from 220-130-178-143.HINET-IP.hinet.net ([220.130.178.143]:58345 "EHLO areca.com.tw") by vger.kernel.org with ESMTP id S932392AbWBXCIW (ORCPT ); Thu, 23 Feb 2006 21:08:22 -0500 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Arjan van de Ven Cc: "\"\"\"Christoph Hellwig\"\"\"" , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, billion.wu@areca.com.tw, alan@lxorguk.ukuu.org.uk, akpm@osdl.org, oliver@neukum.org Dear Arjan van de Ven, I would keep dma_alloc_coherent usage. > [Exception is that you can say that you are ok with a bigger mask for > this type of memory, but just don't do that if you're not] Should I remove "pci_set_dma_mask(pci_device, DMA_64BIT_MASK)" for this case? Best Regards Erich Chen ----- Original Message ----- From: "Arjan van de Ven" To: "erich" Cc: """Christoph Hellwig""" ; ; ; ; ; ; Sent: Thursday, February 23, 2006 8:07 PM Subject: Re: Areca RAID driver remaining items? > On Thu, 2006-02-23 at 19:51 +0800, erich wrote: >> If Linux can not assurent the contingous memory space allocating of >> "dma_alloc_coherent" . > > coherent memory is guaranteed to be in the "lower" 32 bit of memory! > So that is good news, I think you are just fine. > > [Exception is that you can say that you are ok with a bigger mask for > this type of memory, but just don't do that if you're not] > > >> When arcmsr get a physical ccb address from areca's firmware. >> Does linux has any functions for converting of "bus to virtual" ? > > not without using pools. You would have to search the list of memory you > gave it to find that out. > > (USB has a similar problem, afaik they solved it with pools) > >