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From: Jani Nikula <jani.nikula@linux.intel.com>
To: "Hans de Goede" <hdegoede@redhat.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>,
	stable@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: Fix not finding the VBT when it overlaps with OPREGION_ASLE_EXT
Date: Fri, 10 Feb 2017 14:21:07 +0200	[thread overview]
Message-ID: <87d1eqs0cs.fsf@intel.com> (raw)
In-Reply-To: <51453855-216b-1966-226f-b223badf61b7@redhat.com>

On Fri, 10 Feb 2017, Hans de Goede <hdegoede@redhat.com> wrote:
> On 06-02-17 08:04, Jani Nikula wrote:
>> First, I want a big fat warning comment about what's going on
>> here. Otherwise someone's bound to "fix" this later on.
>
> Done for v2, which I will send shortly.

Thanks.

>> Second, per the spec, the ASLE ext mailbox is 1k in size, and there's a
>> 1k reserved region at the end. We probably shouldn't allow VBT to extend
>> over there. But hey, per the spec we also shouldn't allow VBT to extend
>> over mailbox #5 either. So if you can't be bothered with that, neither
>> will I.
>
> Hmm, that makes no sense, OPREGION_SIZE is 8192 bytes or 0x2000,
> OPREGION_ASLE_EXT_OFFSET is 0x1C00 or 7168 bytes, if there is 1k
> reserved after the ASLE ext mailbox then there is exactly 0 bytes
> available for the ASLE ext mailbox or OPREGION_SIZE should be 9216
> not 8192 (which I don't think so). Maybe the last 1k is either
> the ASLE ext mailbox OR reserved ?

You're quite right, that makes no sense. :) Looks like we account for
the reserved part at the end of struct opregion_asle_ext, but the spec
isn't quite clear whether the reserved part is actually part of the
mailbox or not. I'm not quite sure how I managed to confuse myself to
turn that into 1k. Sorry.

BR,
Jani.

-- 
Jani Nikula, Intel Open Source Technology Center
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

WARNING: multiple messages have this Message-ID (diff)
From: Jani Nikula <jani.nikula@linux.intel.com>
To: "Hans de Goede" <hdegoede@redhat.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>,
	dri-devel@lists.freedesktop.org, stable@vger.kernel.org
Subject: Re: [PATCH] drm/i915: Fix not finding the VBT when it overlaps with OPREGION_ASLE_EXT
Date: Fri, 10 Feb 2017 14:21:07 +0200	[thread overview]
Message-ID: <87d1eqs0cs.fsf@intel.com> (raw)
In-Reply-To: <51453855-216b-1966-226f-b223badf61b7@redhat.com>

On Fri, 10 Feb 2017, Hans de Goede <hdegoede@redhat.com> wrote:
> On 06-02-17 08:04, Jani Nikula wrote:
>> First, I want a big fat warning comment about what's going on
>> here. Otherwise someone's bound to "fix" this later on.
>
> Done for v2, which I will send shortly.

Thanks.

>> Second, per the spec, the ASLE ext mailbox is 1k in size, and there's a
>> 1k reserved region at the end. We probably shouldn't allow VBT to extend
>> over there. But hey, per the spec we also shouldn't allow VBT to extend
>> over mailbox #5 either. So if you can't be bothered with that, neither
>> will I.
>
> Hmm, that makes no sense, OPREGION_SIZE is 8192 bytes or 0x2000,
> OPREGION_ASLE_EXT_OFFSET is 0x1C00 or 7168 bytes, if there is 1k
> reserved after the ASLE ext mailbox then there is exactly 0 bytes
> available for the ASLE ext mailbox or OPREGION_SIZE should be 9216
> not 8192 (which I don't think so). Maybe the last 1k is either
> the ASLE ext mailbox OR reserved ?

You're quite right, that makes no sense. :) Looks like we account for
the reserved part at the end of struct opregion_asle_ext, but the spec
isn't quite clear whether the reserved part is actually part of the
mailbox or not. I'm not quite sure how I managed to confuse myself to
turn that into 1k. Sorry.

BR,
Jani.

-- 
Jani Nikula, Intel Open Source Technology Center

  reply	other threads:[~2017-02-10 12:21 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-25 10:19 [PATCH] drm/i915: Fix not finding the VBT when it overlaps with OPREGION_ASLE_EXT Hans de Goede
2016-12-25 10:19 ` Hans de Goede
2016-12-27 10:58 ` Jani Nikula
2016-12-27 10:58   ` Jani Nikula
2016-12-31 16:00   ` Hans de Goede
2017-01-20  8:07     ` Hans de Goede
2017-01-20  8:07       ` Hans de Goede
2017-01-20  8:16       ` Jani Nikula
2017-01-20  8:16         ` Jani Nikula
2017-01-23 10:36       ` Jani Nikula
2017-01-23 10:36         ` Jani Nikula
2017-01-23 16:04         ` Hans de Goede
2017-01-24 13:33           ` Jani Nikula
2017-02-04 13:51           ` Hans de Goede
2017-02-06  6:55             ` Jani Nikula
2017-02-06  7:04 ` Jani Nikula
2017-02-06  7:04   ` Jani Nikula
2017-02-10 10:52   ` Hans de Goede
2017-02-10 10:52     ` Hans de Goede
2017-02-10 12:21     ` Jani Nikula [this message]
2017-02-10 12:21       ` Jani Nikula

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