From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH] drm/i915:: Disable FBC on SandyBridge Date: Tue, 17 Jan 2012 11:16:01 +0000 Message-ID: References: <1320794254-3114-1-git-send-email-chris@chris-wilson.co.uk> <20120117105705.GH4093@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTP id 68A849F572 for ; Tue, 17 Jan 2012 03:16:12 -0800 (PST) In-Reply-To: <20120117105705.GH4093@phenom.ffwll.local> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Daniel Vetter , Eugeni Dodonov Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Tue, 17 Jan 2012 11:57:05 +0100, Daniel Vetter wrote: > On Tue, Nov 08, 2011 at 11:17:34PM +0000, Chris Wilson wrote: > > Enabling FBC is causing the BLT ring to run between 10-100x slower than > > normal and frequently lockup. The interim solution is disable FBC once > > more until we know why. > > > > Signed-off-by: Chris Wilson > > Iirc fbc isn't really worth it power-wise on snb and we don't implement it on > ivb. So shouldn't we just disable it completely? Eugeni, any opinions - I > think you're most up to speed on power saving figures for snb? Also note that I've had a couple of people confirm this bug and tested the patch on IRC. Doesn't help explain precisely what is wrong nor if there is a better workaround amidst the chicken bits that we've missed. -Chris -- Chris Wilson, Intel Open Source Technology Centre