From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 0/9] TI DMM-TILER driver Date: Thu, 16 Dec 2010 18:43:48 +0100 Message-ID: <201012161843.48262.arnd@arndb.de> References: <1291674446-10766-1-git-send-email-davidsin@ti.com> <20101216172531.GG29435@lba0869738> <20101216173737.GA6767@lba0869738> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20101216173737.GA6767@lba0869738> Sender: linux-kernel-owner@vger.kernel.org To: David Sin Cc: linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, Greg KH , Russell King , Andrew Morton , linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org List-Id: linux-omap@vger.kernel.org On Thursday 16 December 2010 18:37:38 David Sin wrote: > I'm not sure exactly how DRM/GEM works.. What functionality do you think is > overlapping? The main feature, aside from reduced page accesses, of the DMM > hw block is to provide physically contiguous 2 dimensional memory blocks for > image and video processing. This hw sits between the interconnect and the > ext memory interface in the OMAP, and contains an MMU-like address traslator > for "virtually" physically contiguous memory and sdram pages. As far as I can tell, both DMM and GEM at a high level manage objects in video memory. The IOMMU that you have on the Omap hardware seems to resemble the GART that sits between PC-style video cards and main memory. I don't know any details, but google quickly finds http://lwn.net/Articles/283798/ with a description of the initial GEM design. My main thought when looking over the DMM code was that this should not be tied too closely to a specific hardware, and GEM seems to be an existing abstraction that may fit what you need. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Thu, 16 Dec 2010 18:43:48 +0100 Subject: [PATCH 0/9] TI DMM-TILER driver In-Reply-To: <20101216173737.GA6767@lba0869738> References: <1291674446-10766-1-git-send-email-davidsin@ti.com> <20101216172531.GG29435@lba0869738> <20101216173737.GA6767@lba0869738> Message-ID: <201012161843.48262.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thursday 16 December 2010 18:37:38 David Sin wrote: > I'm not sure exactly how DRM/GEM works.. What functionality do you think is > overlapping? The main feature, aside from reduced page accesses, of the DMM > hw block is to provide physically contiguous 2 dimensional memory blocks for > image and video processing. This hw sits between the interconnect and the > ext memory interface in the OMAP, and contains an MMU-like address traslator > for "virtually" physically contiguous memory and sdram pages. As far as I can tell, both DMM and GEM at a high level manage objects in video memory. The IOMMU that you have on the Omap hardware seems to resemble the GART that sits between PC-style video cards and main memory. I don't know any details, but google quickly finds http://lwn.net/Articles/283798/ with a description of the initial GEM design. My main thought when looking over the DMM code was that this should not be tied too closely to a specific hardware, and GEM seems to be an existing abstraction that may fit what you need. Arnd