From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [PATCH] drm/i915: BIOS and power context stolen mem
 handling for VLV v6
Date: Tue, 7 May 2013 22:57:37 +0100
Message-ID: <20130507215736.GA22739@cantiga.alporthouse.com>
References: <1367959066-2381-1-git-send-email-jbarnes@virtuousgeek.org>
	<1367962471-3534-1-git-send-email-jbarnes@virtuousgeek.org>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org>
Received: from mga03.intel.com (mga03.intel.com [143.182.124.21])
	by gabe.freedesktop.org (Postfix) with ESMTP id 48D01E5CCE
	for <intel-gfx@lists.freedesktop.org>;
	Tue,  7 May 2013 14:57:40 -0700 (PDT)
Content-Disposition: inline
In-Reply-To: <1367962471-3534-1-git-send-email-jbarnes@virtuousgeek.org>
List-Unsubscribe: <http://lists.freedesktop.org/mailman/options/intel-gfx>,
	<mailto:intel-gfx-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <http://lists.freedesktop.org/archives/intel-gfx>
List-Post: <mailto:intel-gfx@lists.freedesktop.org>
List-Help: <mailto:intel-gfx-request@lists.freedesktop.org?subject=help>
List-Subscribe: <http://lists.freedesktop.org/mailman/listinfo/intel-gfx>,
	<mailto:intel-gfx-request@lists.freedesktop.org?subject=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: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: intel-gfx@lists.freedesktop.org
List-Id: intel-gfx@lists.freedesktop.org

On Tue, May 07, 2013 at 02:34:31PM -0700, Jesse Barnes wrote:
> +static void valleyview_setup_pctx(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_i915_gem_object *pctx;
> +	unsigned long pctx_paddr;
> +	u32 pcbr;
> +	int pctx_size = 24*1024;
> +
> +	pcbr = I915_READ(VLV_PCBR);
> +	if (pcbr) {
> +		/* BIOS set it up already, grab the pre-alloc'd space */
> +		int pcbr_offset;
> +
> +		pcbr_offset = (pcbr & (~4095)) - dev_priv->mm.stolen_base;
> +		pctx = i915_gem_object_create_stolen_for_preallocated(dev_priv->dev,
> +								      pcbr_offset,
> +								      pcbr_offset,
> +								      pctx_size);

We're reserving global GTT space here for someting that just looks like
it requires contiguous physical memory. This may cause issues if
something else is already bound to that GTT range. I think we want to
extend the interface to not reserve GTT space if gtt_offset == -1.

Much happier with the placement of functions and the comments help a
lot.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre