From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt_Domsch@Dell.com Date: Mon, 09 Jul 2001 15:20:28 +0000 Subject: RE: [Linux-ia64] RE: DMA memory limitation? Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org > My device has the limitation that the command buffers I send > must be in 32 > bit space, but the IO can be in 64 bit. But there is only > ONE dma_mask for the device. Ahh, yes. The AMI MegaRAID driver/controllers have the same requirements. megaraid solved it as: pci_find_device() finds their device, they get a pci_dev back which has a 32-bit dma_mask. pci_alloc_consistent() the mailbox (this must be in 32-bit space). if it's a 64-bit-capable controller, set pci_dev->dma_mask = ~0L. pci_alloc_consistent() the command buffers and scatter-gather lists (these can be in 64-bit space). Could something similar work for you? Thanks, Matt -- Matt Domsch Sr. Software Engineer Dell Linux Solutions www.dell.com/linux #2 Linux Server provider with 17% in the US and 14% Worldwide (IDC)! #3 Unix provider with 18% in the US (Dataquest)!