[Intel-gfx] [PATCH i-g-t 3/4] igt_kms: Do not reset plane position on assigning a fb

[Konduru, Chandra]

> -----Original Message-----
> From: Tvrtko Ursulin [mailto:tvrtko.ursulin at linux.intel.com]
> Sent: Thursday, May 07, 2015 2:15 AM
> To: Konduru, Chandra; Intel-gfx at lists.freedesktop.org
> Cc: Ursulin, Tvrtko
> Subject: Re: [PATCH i-g-t 3/4] igt_kms: Do not reset plane position on assigning
> a fb
> 
> 
> On 05/06/2015 08:02 PM, Konduru, Chandra wrote:
> >
> >> diff --git a/lib/igt_kms.c b/lib/igt_kms.c index b5ba273..0665d70
> >> 100644
> >> --- a/lib/igt_kms.c
> >> +++ b/lib/igt_kms.c
> >> @@ -1765,9 +1765,7 @@ void igt_plane_set_fb(igt_plane_t *plane,
> >> struct igt_fb *fb)
> >>   	plane->fb = fb;
> >>   	/* hack to keep tests working that don't call igt_plane_set_size() */
> >>   	if (fb) {
> >> -		/* set default plane pos/size as fb size */
> >> -		plane->crtc_x = 0;
> >> -		plane->crtc_y = 0;
> > Reason for doing this is to make existing kms tests to run without
> modification.
> > Otherwise every existing test has to explicitly call
> > igt_plane_set_position to make sure it works. Can you make sure removing
> above 2 lines doesn't break existing tests?
> 
> Hm, before your patch tests could set a plane position, change the fb, and plane
> position would remain the same. After your patch changing the fb resets the
> plane position. My patch reverts this behaviour to old one.
> 
> So I am not sure in what cases resetting plane position on fb changes helps and
> which tests?
> 
> Which tests do you think should be run?
> 
Ignore my previous comment, I was thinking that this change will
make plane->crtc_x/y uninitialized before calling igt_drm_plane_commit. 
But igt_display_init() does memsets display which will initialize these to 0s. 
So no initialization required as part here. Your changes are fine.

> Regards,
> 
> Tvrtko