[Mesa-dev] [PATCH 2/2] i965: Advertise 8 subpixel bits always.

[Francisco Jerez]

Chris Forbes <chrisforbes at google.com> writes:

> Hi Curro,
>
> Thanks for being thorough about this -- I think there is still one area
> where things might be a bit wobbly; if we end up taking a sw fallback,
> swrast only does 4 bits. I'm not sure that matters though.
>
Hmm, I don't think we fall back to swrast for anything that would be
sensitive to the subpixel precision, but it's definitely worth
checking. :)

> - Chris
>
> On Tue, Nov 8, 2016 at 11:01 AM, Francisco Jerez <currojerez at riseup.net>
> wrote:
>
>> Chris Forbes <chrisf at ijw.co.nz> writes:
>>
>> > The mesa default is 4, but we program the hardware for 8 on all
>> > generations.
>> >
>>
>> I happened to come across this inconsistency a couple of weeks ago -- I
>> just double-checked that it doesn't cause any conformance regressions
>> because some of the rasterization tests use the GL_SUBPIXEL_BITS value
>> to determine the error tolerance so increasing the value could
>> potentially uncover additional approximation errors.  Doesn't seem to
>> cause any regressions though in our CI system, series is:
>>
>> Reviewed-by: Francisco Jerez <currojerez at riseup.net>
>>
>> > Signed-off-by: Chris Forbes <chrisforbes at google.com>
>> > ---
>> >  src/mesa/drivers/dri/i965/brw_context.c | 1 +
>> >  1 file changed, 1 insertion(+)
>> >
>> > diff --git a/src/mesa/drivers/dri/i965/brw_context.c
>> b/src/mesa/drivers/dri/i965/brw_context.c
>> > index 3085a98..d8174c6 100644
>> > --- a/src/mesa/drivers/dri/i965/brw_context.c
>> > +++ b/src/mesa/drivers/dri/i965/brw_context.c
>> > @@ -538,6 +538,7 @@ brw_initialize_context_constants(struct brw_context
>> *brw)
>> >        ctx->Const.MaxProgramTextureGatherComponents = 1;
>> >
>> >     ctx->Const.MaxUniformBlockSize = 65536;
>> > +   ctx->Const.SubPixelBits = 8;
>> >
>> >     for (int i = 0; i < MESA_SHADER_STAGES; i++) {
>> >        struct gl_program_constants *prog = &ctx->Const.Program[i];
>> > --
>> > 2.10.2
>> >
>> > _______________________________________________
>> > mesa-dev mailing list
>> > mesa-dev at lists.freedesktop.org
>> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>>
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