[Mesa-dev] [PATCH] i965: consider a 'base level' when calculating width0, height0, depth0

[andrey simiklit]

Hello,

The test for this issue is pushed to the piglit.
It would be great to push the mesa fix too if it is still an acceptable for
all :)

Thanks,
Andrii.
On Sat, Oct 20, 2018 at 12:29 PM andrey simiklit <asimiklit.work at gmail.com>
wrote:

> Hello,
>
> On Fri, Oct 19, 2018 at 15:14 Kenneth Graunke <kenneth at whitecape.org>
> wrote:
>
>> On Thursday, October 11, 2018 12:12:38 PM PDT Kenneth Graunke wrote:
>> > On Thursday, October 11, 2018 11:58:40 AM PDT Kenneth Graunke wrote:
>> > > On Tuesday, October 2, 2018 9:16:01 AM PDT asimiklit.work at gmail.com
>> wrote:
>> > > > From: Andrii Simiklit <andrii.simiklit at globallogic.com>
>> > > >
>> > > > I guess that when we calculating the width0, height0, depth0
>> > > > to use for function 'intel_miptree_create' we need to consider
>> > > > the 'base level' like it is done in the
>> 'intel_miptree_create_for_teximage'
>> > > > function.
>> > > >
>> > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107987
>> > > > Signed-off-by: Andrii Simiklit <andrii.simiklit at globallogic.com>
>> > > > ---
>> > > >  .../drivers/dri/i965/intel_tex_validate.c     | 26
>> ++++++++++++++++++-
>> > > >  1 file changed, 25 insertions(+), 1 deletion(-)
>> > >
>> > > I believe this patch is correct - we're assembling things into a new
>> > > miptree, which we start at level 0 - so we need the sizes for level 0.
>> > >
>> > > Alternatively, we might be able to pass validate_first_level instead
>> > > of 0 when calling intel_miptree_create, to make one that's only good
>> > > up until the new base...and have to re-assemble it the next time they
>> > > change the base.  It would save memory potentially.  But more copies.
>> > > I don't have a strong preference which is better.
>> > >
>> > > Please do make a Piglit or dEQP test for this.
>> > >
>> > > Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
>> >
>> > Sorry, withdrawing my review. :(  Chris Forbes pointed out on IRC that
>> > your reproducer case is backwards:
>> >
>> > miplevel 0 - 1x1
>> > miplevel 1 - 2x2
>> > miplevel 2 - 4x4
>> >
>> > That's upside down.  A proper miptree would have the base be largest:
>> >
>> > miplevel 0 - 4x4
>> > miplevel 1 - 2x2
>> > miplevel 2 - 1x1
>> >
>> > So, yes, I could see this tripping an assert...but such a crazy texture
>> > will never be mipmap complete.  If they're expecting mipmapping, then
>> > it seems like they should get a fallback black texture (which normally
>> > happens for incomplete textures).  If not, maybe they should get a
>> > single miplevel?  Either way, seems like we should detect insanity and
>> > bail, rather than change size calculations for the normal sane case.
>> >
>>
>> So...looked at this again.  I'm not sure why upside-down matters.
>>
>> At DrawArrays time, we have a single miplevel (base = 2), and are trying
>> to put that single miplevel's image into a miptree.  We do properly
>> ignore levels 0..1 as they're beyond the base.
>>
>> We appear to use level 0 as the actual base, and want to store our
>> single level at level 2.  Other places (TexImage) seem to work that way
>> too.
>>
>> But, we're creating the miplevel with level 0 as the base, but where
>> level 0 has the dimensions of level 2.  This doesn't work.  And your
>> patch fixes that.
>>
>> I tried making the actual base of the unified tree be level 2, rather
>> than level 0...so that the BaseLevel is the actual base...but tons of
>> things broke.
>>
>> So, back to Reviewed-by.  I think once we get a Piglit test, I'm happy
>> to land this patch.
>
>
> Thanks for reviewing :-) I will start to work on it as soon as come back
> from vacation (on Monday)
>
>
>>
>> --Ken
>
>
> Thanks,
> Andrii.
>
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