From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Hellstrom Subject: Re: [PATCH] drm/ttm: Only try to preserve caching in moves in the same space Date: Mon, 01 Feb 2010 17:18:13 +0100 Message-ID: <4B66FEC5.9050503@vmware.com> References: <1264670799-16101-1-git-send-email-luca@luca-barbieri.com> <21d7e9971001311735q3718ad8dy5298f19175a79a6e@mail.gmail.com> <20100201133317.GH29000@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100201133317.GH29000@localhost.localdomain> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.sourceforge.net To: Jerome Glisse Cc: "airlied@linux.ie" , Jerome Glisse , Luca Barbieri , "dri-devel@lists.sourceforge.net" List-Id: dri-devel@lists.freedesktop.org Jerome Glisse wrote: > On Mon, Feb 01, 2010 at 11:35:21AM +1000, Dave Airlie wrote: > >> On Thu, Jan 28, 2010 at 7:26 PM, Luca Barbieri wrote: >> >>> Currently TTM tries to preserve the previous caching even for moves >>> between unrelated memory spaces. >>> >>> This results for instance in moves from VRAM to PCIE GART changing >>> system memory to WC state needlessly. >>> >>> This patch changes TTM to only try to preserve caching if moving from >>> system/TT to system/TT. >>> >>> In theory, we should also do that if moving between two device memory >>> spaces that are backend by the same physical memory area. >>> However, I'm not sure how to do that in the current TTM framework and >>> I suspect no card/driver uses memory spaces in that way. >>> >> Thomas or Jerome (since I think placement changes were you), any >> chance of ack or review? >> >> Dave. >> >> > > I think i will NACK, the idea to avoid switching to WC is good but i think it > can be achieve with current code by using cleverly the infrastructure. > I agree with Jerome. It *should* be possible to have the driver control this sort of thing depending on what triggered the validate / move call. Thanks, Thomas ------------------------------------------------------------------------------ The Planet: dedicated and managed hosting, cloud storage, colocation Stay online with enterprise data centers and the best network in the business Choose flexible plans and management services without long-term contracts Personal 24x7 support from experience hosting pros just a phone call away. http://p.sf.net/sfu/theplanet-com --