From: David Woodhouse <dwmw2@infradead.org>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: rajesh.sankaran@intel.com, Keith Packard <keithp@keithp.com>,
Matthew Garrett <mjg@redhat.com>,
intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: By default, enable RC6 on IVB and SNB when reasonable
Date: Wed, 23 Nov 2011 15:03:43 +0000 [thread overview]
Message-ID: <1322060623.15493.168.camel@shinybook.infradead.org> (raw)
In-Reply-To: <20111123143931.GE3864@phenom.ffwll.local>
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On Wed, 2011-11-23 at 15:39 +0100, Daniel Vetter wrote:
> At least for the dmar+gfx+semaphores hang I can reproduce, just disabling
> dmar with intel_iommu=igfx_off is not good enough and iirc the same holds
> for the dmar+rc6 hangs reported.
Um... let me restate that for clarity (and partly for Rajesh's benefit).
The DMAR associated with the integrated graphics is *disabled*.
Turned off. Not active. Ever.
You have a problem when you enable the *other* DMAR units in the system,
which should not be affecting the graphics device in any way.
When you do this, you see 'hangs' with semaphores and RC6. Is there a
better description of these 'hangs' somewhere? Is the hardware
completely locked?
These hangs go away when you disable the DMAR units. Again, that is the
*other* DMAR units in the system that have nothing to do with graphics.
While I'm getting quite used to DMAR-related errata, this one does make
me stop and think 'wtf?'. It just seems so incongruous that disabling an
*unrelated* IOMMU would make the problem go away, and it makes me wonder
if it's actually a timing-related issue which is always there, but
something about the use of DMAR for network/disk/etc. makes it more
likely to trigger?
We definitely need the hardware folks to get to the bottom of this one.
--
dwmw2
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next prev parent reply other threads:[~2011-11-23 15:03 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-19 6:41 [PATCH] drm/i915: By default, enable RC6 on IVB and SNB when reasonable Keith Packard
2011-11-19 7:37 ` [Intel-gfx] " Kenneth Graunke
2011-11-19 9:25 ` Eugeni Dodonov
2011-11-19 18:32 ` Keith Packard
2011-11-20 21:19 ` Eugeni Dodonov
2011-11-22 20:15 ` Matthew Garrett
[not found] ` <CAC7Lmnts+QwZ2XTvbTQa=aa3XO5_Sna0vk3KHWJJ6oi6+D5BXw@mail.gmail.com>
2011-11-22 20:51 ` Matthew Garrett
2011-11-23 3:31 ` Keith Packard
2011-11-23 10:26 ` Daniel Vetter
2011-11-23 14:01 ` David Woodhouse
2011-11-23 14:39 ` Daniel Vetter
2011-11-23 15:03 ` David Woodhouse [this message]
2011-11-23 15:31 ` Daniel Vetter
2011-11-23 15:36 ` David Woodhouse
2011-11-23 15:46 ` Daniel Vetter
2011-11-23 15:41 ` Daniel Vetter
2011-11-23 15:43 ` David Woodhouse
2011-11-23 20:35 ` Daniel Vetter
2011-11-23 18:42 ` [PATCH] iommu: export no_iommu and dmar_disabled symbols Eugeni Dodonov
2011-11-23 20:36 ` [Intel-gfx] " David Woodhouse
2011-11-23 20:48 ` Keith Packard
[not found] ` <1322526298-2746-1-git-send-email-eugeni.dodonov@intel.com>
2011-12-09 23:53 ` drm/i915: Enabling RC6 where possible Keith Packard
2011-12-09 23:53 ` [PATCH 1/2] iommu: Export intel_iommu_enabled to signal when iommu is in use Keith Packard
2011-12-09 23:53 ` [PATCH 2/2] drm/i915: By default, enable RC6 on IVB and SNB when reasonable Keith Packard
2011-12-13 3:45 ` Matthew Garrett
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