[igt-dev] [i-g-t V2] tests/kms_prime: Use 256B aligned width

[Surendrakumar Upadhyay, TejaskumarX]

> -----Original Message-----
> From: Kempczynski, Zbigniew <zbigniew.kempczynski at intel.com>
> Sent: 23 July 2021 12:56
> To: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Surendrakumar Upadhyay, TejaskumarX
> <tejaskumarx.surendrakumar.upadhyay at intel.com>; IGT development <igt-
> dev at lists.freedesktop.org>
> Subject: Re: [igt-dev] [i-g-t V2] tests/kms_prime: Use 256B aligned width
> 
> On Thu, Jul 22, 2021 at 02:55:47PM +0200, Daniel Vetter wrote:
> > On Tue, Jul 20, 2021 at 1:05 PM Tejas Upadhyay
> > <tejaskumarx.surendrakumar.upadhyay at intel.com> wrote:
> > >
> > > Having different alignment requirement by different drivers, 256B
> > > aligned should work for all drm drivers.
> > >
> > > amdgpu and radeon, amdgpu_align_pitch: 256B armada, armada_pitch:
> > > 128B
> > > exynos_drm_gem_dumb_create: No alignment required
> > > drm_gem_shmem_dumb_create: 8B
> > > drm_gem_vram_fill_create_dumb: 8B
> > >
> > > Thus 256B covers everything we see in the kernel drm drivers.
> > >
> > > Changes since V1:
> > >         - Edited commit message with driver compatible with 256B
> > > align-Daniel
> > >
> > > Signed-off-by: Tejas Upadhyay
> > > <tejaskumarx.surendrakumar.upadhyay at intel.com>
> >
> > Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> 
> Why we should create bigger dumb buffer on specific driver than required?

In order to have generic minimum align requirement across vendor drivers, we need to put 256B.

Thanks,
Tejas
> 
> --
> Zbigniew
> 
> 
> >
> > > ---
> > >  tests/kms_prime.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/tests/kms_prime.c b/tests/kms_prime.c index
> > > 35f4b5b7..2e20c58b 100644
> > > --- a/tests/kms_prime.c
> > > +++ b/tests/kms_prime.c
> > > @@ -101,7 +101,7 @@ static void prepare_scratch(int exporter_fd, struct
> dumb_bo *scratch,
> > >         scratch->bpp = 32;
> > >
> > >         scratch->handle = kmstest_dumb_create(exporter_fd,
> > > -                       scratch->width,
> > > +                       ALIGN(scratch->width, 256),
> > >                         scratch->height,
> > >                         scratch->bpp,
> > >                         &scratch->pitch,
> > > --
> > > 2.31.1
> > >
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> >
> >
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
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