Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755449Ab0LEVnH (ORCPT ); Sun, 5 Dec 2010 16:43:07 -0500 Received: from mga09.intel.com ([134.134.136.24]:20062 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752998Ab0LEVnG (ORCPT ); Sun, 5 Dec 2010 16:43:06 -0500 Message-Id: X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.59,302,1288594800"; d="scan'208";a="580777100" Date: Sun, 05 Dec 2010 21:43:02 +0000 To: Sriram , linux-kernel@vger.kernel.org Subject: Re: [drm:init_ring_common] *ERROR* render ring head not reset to zero In-Reply-To: References: <201010042231.20320.thomas@m3y3r.de> <8u3s8d$jp78ts@orsmga001.jf.intel.com> From: Chris Wilson Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 749 Lines: 18 On Sun, 5 Dec 2010 06:28:25 +0000 (UTC), Sriram wrote: > Please explain what this error means & why it is happening... We wrote a zero into the register (whilst the ring is completely idle, supposedly anyway) and read back a non-zero value. We believe the silicon is doing evil things, we workaround it by writing the value again, and continue on our merry way. The dance only gets more complex as the hardware evolves. -Chris -- Chris Wilson, Intel Open Source Technology Centre -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/