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From: "H. Peter Anvin" <hpa@zytor.com>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	mingo@elte.hu, tglx@linutronix.de, torvalds@linux-foundation.org
Subject: Re: [PATCH 2/2] x86: add early quirk for reserving Intel graphics stolen memory v3
Date: Fri, 26 Jul 2013 09:58:45 -0700	[thread overview]
Message-ID: <51F2AAC5.6020808@zytor.com> (raw)
In-Reply-To: <1374770269-3223-3-git-send-email-jbarnes@virtuousgeek.org>

On 07/25/2013 09:37 AM, Jesse Barnes wrote:
> Systems with Intel graphics controllers set aside memory exclusively for
> +	/*
> +	 * Almost universally we can find the Graphics Base of Stolen Memory
> +	 * at offset 0x5c in the igfx configuration space. On a few (desktop)
> +	 * machines this is also mirrored in the bridge device at different
> +	 * locations, or in the MCHBAR.
> +	 */

This comment makes me nervous.  It isn't clear to me if it is saying:

- All igfx devices has the graphics base at 0x5c, a few have it in
  other places, too (which doesn't matter, we can use 0x5c anyway), or
- Most igfx devices have the graphics base at 0x5c, some don't, and we
  hope and pray we're not on one of those systems because we're not
  checking.

I assume it is the former, but it really needs to be phrased better.

	-hpa



  parent reply	other threads:[~2013-07-26 16:59 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-25 16:37 Ugly patches for stolen reservation Jesse Barnes
2013-07-25 16:37 ` [PATCH 1/2] drm/i915: split PCI IDs out into i915_drm.h v3 Jesse Barnes
2013-07-25 23:06   ` Chris Wilson
2013-07-25 16:37 ` [PATCH 2/2] x86: add early quirk for reserving Intel graphics stolen memory v3 Jesse Barnes
2013-07-25 22:42   ` Chris Wilson
2013-07-25 22:59     ` Chris Wilson
2013-07-25 23:18       ` Jesse Barnes
2013-07-26  8:10   ` [Intel-gfx] " Daniel Vetter
2013-07-26 16:58   ` H. Peter Anvin [this message]
2013-07-26 17:12     ` Jesse Barnes
2013-07-25 20:05 ` Ugly patches for stolen reservation Ingo Molnar
2013-07-25 20:16   ` Jesse Barnes
2013-07-25 22:10     ` [Intel-gfx] " Daniel Vetter
2013-07-25 22:42   ` H. Peter Anvin
2013-07-25 23:17     ` Jesse Barnes
2013-07-26  0:49       ` H. Peter Anvin
2013-07-26  0:31     ` Linus Torvalds
2013-07-26  0:48       ` H. Peter Anvin
2013-07-26 17:52         ` [Intel-gfx] " Daniel Vetter
2013-07-26 15:51       ` Jesse Barnes

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