From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21C1DC2D0DB for ; Wed, 29 Jan 2020 19:01:10 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 07534206D4 for ; Wed, 29 Jan 2020 19:01:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 07534206D4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A283C89B96; Wed, 29 Jan 2020 19:01:09 +0000 (UTC) Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id DE01289B96 for ; Wed, 29 Jan 2020 19:01:07 +0000 (UTC) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Jan 2020 10:44:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,378,1574150400"; d="scan'208";a="261902781" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by fmsmga002.fm.intel.com with SMTP; 29 Jan 2020 10:44:15 -0800 Received: by stinkbox (sSMTP sendmail emulation); Wed, 29 Jan 2020 20:44:14 +0200 Date: Wed, 29 Jan 2020 20:44:14 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Chris Wilson Message-ID: <20200129184414.GX13686@intel.com> References: <20200129182034.26138-1-ville.syrjala@linux.intel.com> <20200129182034.26138-6-ville.syrjala@linux.intel.com> <158032272436.13511.14294498438655990456@skylake-alporthouse-com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <158032272436.13511.14294498438655990456@skylake-alporthouse-com> X-Patchwork-Hint: comment User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [Intel-gfx] [PATCH 6/9] drm/i915/dsb: Inline DSB_CTRL writes into intel_dsb_commit() X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, Jan 29, 2020 at 06:32:04PM +0000, Chris Wilson wrote: > Quoting Ville Syrjala (2020-01-29 18:20:31) > > + intel_de_write(dev_priv, DSB_CTRL(pipe, dsb->id), > > + DSB_ENABLE); > > + intel_de_write(dev_priv, DSB_HEAD(pipe, dsb->id), > > + i915_ggtt_offset(dsb->vma)); > > intel_de_write(dev_priv, DSB_TAIL(pipe, dsb->id), > > i915_ggtt_offset(dsb->vma) + tail); > = > I still say this order looks dodgy for a ringbuffer. Is it all truly > latched by DSB_TAIL or might it start passing on being enabled and HEAD > !=3D TAIL? My initial thoughts as well, but indeed it's the tail write that makes it go (or at least that's what the docs say). -- = Ville Syrj=E4l=E4 Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx