From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp.logicpd.com ([174.46.170.145]:52094 "HELO smtp.logicpd.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751564AbbCRPT0 (ORCPT ); Wed, 18 Mar 2015 11:19:26 -0400 Message-ID: <55099773.2010809@logicpd.com> Date: Wed, 18 Mar 2015 10:19:15 -0500 From: Tim Nordell MIME-Version: 1.0 To: Laurent Pinchart CC: , Sakari Ailus Subject: Re: [PATCH v2 25/26] omap3isp: Move to videobuf2 References: <1398083352-8451-1-git-send-email-laurent.pinchart@ideasonboard.com> <2161613.bbRGp2ApSQ@avalon> <550991C2.80503@logicpd.com> <2315546.eR07gyadH5@avalon> In-Reply-To: <2315546.eR07gyadH5@avalon> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Laurent - On 03/18/15 09:59, Laurent Pinchart wrote: > Hi Tim, > The names might be a bit misleading, vb2-dma-contig requires contiguous memory > in the device memory space, not in physical memory. The IOMMU, managed through > dma_map_sg_attrs, should have mapped the userptr buffer contiguously in the > ISP DMA address space. If it hasn't, that's what need to be investigated. I see now that it's the sg_dma_address(...) call that it's using and I was assuming that was the physical memory address for the memory backing up the buffer. So the vb2_dc_get_contiguous_size(...) should be against the view of memory that the IOMMU presents to the OMAP3 ISP? That is, the DMA addresses that the OMAP3 ISP can see? I was assuming it was checking the physical memory layout to it without looking too closely to the code. Armed with that knowledge, I'll dig a little deeper to see if I can figure out what happened here. - Tim