From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: [Intel-gfx] [PATCH v9 5/7] vfio: Define vfio based dma-buf operations Date: Wed, 21 Jun 2017 13:03:31 +0200 Message-ID: <1498043011.5802.5.camel@redhat.com> References: <1497513611-2814-1-git-send-email-xiaoguang.chen@intel.com> <1497513611-2814-6-git-send-email-xiaoguang.chen@intel.com> <1497542438.29252.1.camel@redhat.com> <20170615143833.7526351b@w520.home> <24c4880b-24f5-ea07-834c-c77d3e895c78@nvidia.com> <1497854312.4207.4.camel@redhat.com> <20170619085530.1f5e46dc@w520.home> <237F54289DF84E4997F34151298ABEBC7C56EBE0@SHSMSX101.ccr.corp.intel.com> <1497956256.16795.7.camel@redhat.com> <20170620090004.44ac7fbc@w520.home> <237F54289DF84E4997F34151298ABEBC7C56F3DC@SHSMSX101.ccr.corp.intel.com> <20170620172204.09405cf4@w520.home> <237F54289DF84E4997F34151298ABEBC7C56F843@SHSMSX101.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <237F54289DF84E4997F34151298ABEBC7C56F843@SHSMSX101.ccr.corp.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: "Zhang, Tina" , Alex Williamson Cc: "intel-gfx@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , Kirti Wankhede , "Chen, Xiaoguang" , "intel-gvt-dev@lists.freedesktop.org" , "Lv, Zhiyuan" , "Wang, Zhi A" , "Wang, Zhenyu Z" List-Id: intel-gfx@lists.freedesktop.org On Wed, 2017-06-21 at 09:20 +0000, Zhang, Tina wrote: > Thanks for all the comments. I'm planning to cook the next version of > this patch set How about posting only this patch instead of the whole series until we've settled the interfaces? > Could the following two works? > #define VFIO_DEVICE_FLAGS_DMABUF  (1 << 5)        /* vfio-dmabuf > device */ VFIO_DEVICE_FLAGS_GFX_DMABUF? > 2. vfio_device_gfx_plane_info > struct vfio_device_gfx_plane_info { > __u64 start;-> offset > __u64 drm_format_mod; > __u32 drm_format; > __u32 width; > __u32 height; > __u32 stride; > __u32 size; > __u32 x_pos; > __u32 y_pos; > }; > > Does it make sense to have a "generation" field in the plane_info > > struct (which gets increased each time the struct changes) ? > Well,  Gerd, can you share more details about how to use this field > in user mode, so that we can figure out a way to support it? Thanks. generation would be increased each time one of the fields in vfio_device_gfx_plane_info changes, typically on mode switches (width/height changes) and pageflips (offset changes). So userspace can simply compare generation instead of comparing every field to figure whenever something changed compared to the previous poll. > > 3. vfio_device_query_gfx_plane > struct vfio_device_query_gfx_plane { > __u32 argsz; > __u32 flags; > #define VFIO_GFX_PLANE_FLAGS_REGION_ID (1 << 0) > #define VFIO_GFX_PLANE_FLAGS_PLANE_ID (1 << 1) > struct vfio_device_gfx_plane_info plane_info; > __u32 id; > __u32 plane_type; > }; > So far, dmabuf use id for DRM_PLANE_TYPE_PRIMARY or > DRM_PLANE_TYPE_CURSOR. > If the newly added plane_type is used for this, the id field may be > useless in dmabuf usage. Do you have any idea about the usage of this > id field in dmabuf usage? plane_type should be DRM_PLANE_TYPE_PRIMARY or DRM_PLANE_TYPE_CURSOR for dmabuf. Given that nvidia doesn't support a separate cursor plane in their region they would support DRM_PLANE_TYPE_PRIMARY only. I can't see yet what id would be useful for. Likewise I can't see yet what the VFIO_GFX_PLANE_FLAGS_* are good for. cheers, Gerd