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From: Mika Kuoppala <mika.kuoppala@linux.intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>,
	Michel Thierry <michel.thierry@intel.com>
Cc: intel-gfx@lists.freedesktop.org, miku@iki.fi
Subject: Re: [PATCH 2/4] drm/i915/gtt: Warn if the next layer scratch dma is invalid
Date: Wed, 01 Jul 2015 13:55:00 +0300	[thread overview]
Message-ID: <877fqkp2pn.fsf@gaia.fi.intel.com> (raw)
In-Reply-To: <20150630171105.GL1381@nuc-i3427.alporthouse.com>

Chris Wilson <chris@chris-wilson.co.uk> writes:

> On Tue, Jun 30, 2015 at 05:59:27PM +0100, Michel Thierry wrote:
>> On 6/30/2015 4:16 PM, Mika Kuoppala wrote:
>> >When dma page is setup, warn if we try to point the entries
>> >to a uninitialized (zero) dma address. Like we do with gen6
>
> Just a note that 0 looks only to be reserved due to a quirk of the
> intel-iommu implementation. There is nothing preventing a different
> iommu or future implementation using 0 as a valid dma_addr_t afaict.
>
> This should presumably be
> WARN_ON(dma_mapping_error(&dev->pdev->dev, px_dma()));
> -Chris
>

Ah yes. This was my paranoia from the times we updated
execlists pdps with zero dma addresses.

Michel pointed out that we do a proper dma_mapping_error 
check when we allocate the dma page. So I think this patch
can be ignored.

-Mika

> -- 
> Chris Wilson, Intel Open Source Technology Centre
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  reply	other threads:[~2015-07-01 10:55 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-30 15:16 [PATCH 1/4] drm/i915/gtt: Reorder page alloc/free/init functions Mika Kuoppala
2015-06-30 15:16 ` [PATCH 2/4] drm/i915/gtt: Warn if the next layer scratch dma is invalid Mika Kuoppala
2015-06-30 16:59   ` Michel Thierry
2015-06-30 17:11     ` Chris Wilson
2015-07-01 10:55       ` Mika Kuoppala [this message]
2015-06-30 15:16 ` [PATCH 3/4] drm/i915/gtt: Return struct i915_scratch_page from alloc_scratch Mika Kuoppala
2015-07-01 12:02   ` Michel Thierry
2015-07-01 13:15     ` Daniel Vetter
2015-06-30 15:16 ` [PATCH 4/4] drm/i915/gtt: Per ppgtt scratch page Mika Kuoppala
2015-07-01 14:05   ` Michel Thierry
2015-07-01 14:26     ` Daniel Vetter
2015-07-01 14:25       ` Michel Thierry
2015-07-01 14:49         ` Daniel Vetter
2015-07-02 14:34   ` shuang.he
2015-06-30 16:58 ` [PATCH 1/4] drm/i915/gtt: Reorder page alloc/free/init functions Michel Thierry

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