From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933696AbcHJXFP (ORCPT ); Wed, 10 Aug 2016 19:05:15 -0400 Received: from ec2-52-27-115-49.us-west-2.compute.amazonaws.com ([52.27.115.49]:40355 "EHLO s-opensource.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932424AbcHJXFO (ORCPT ); Wed, 10 Aug 2016 19:05:14 -0400 Subject: Re: [PATCH] exynos-drm: Fix display manager failing to start without IOMMU problem To: Inki Dae , jy0922.shim@samsung.com, sw0312.kim@samsung.com, kyungmin.park@samsung.com, airlied@linux.ie, kgene@kernel.org, k.kozlowski@samsung.com References: <1470850251-9150-1-git-send-email-shuahkh@osg.samsung.com> <57ABB1ED.1080301@samsung.com> Cc: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Shuah Khan From: Shuah Khan Message-ID: <57ABB31E.1070802@osg.samsung.com> Date: Wed, 10 Aug 2016 17:05:02 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <57ABB1ED.1080301@samsung.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/10/2016 04:59 PM, Inki Dae wrote: > Hi Shuah, > > 2016년 08월 11일 02:30에 Shuah Khan 이(가) 쓴 글: >> Fix exynos_drm_gem_create_ioctl() attempts to allocate non-contiguous GEM >> memory without IOMMU. In this case, there is no point in attempting to > > DRM gem can be used for Non-DRM drivers such as GPU, V4L2 based Multimedia device and other DMA devices. > Even though IOMMU support is disabled, other framework based DMA drivers can use IOMMU - i.e., GPU driver - > and they can use non-contiguous GEM buffer through UMM. (DMABUF) > > So GEM allocation type is not dependent on IOMMU. Hi Inki, I am seeing the following failure without IOMMU and light dm fails to start: [drm:exynos_drm_framebuffer_init] *ERROR* Non-continguous GEM memory is not supported. The change I made fixed that problem and light dm starts without IOMMU. Is there a better way to fix this problem? Currently without IOMMU, light dm doesn't start. This is on linux_next thanks, -- Shuah