[Intel-gfx] [PATCH v2 6/6] drm/i915: Do not do fb src adjustments for NV12

Tue Apr 17 08:09:30 UTC 2018

> -----Original Message-----
> From: Srinivas, Vidya
> Sent: Tuesday, April 17, 2018 1:32 PM
> To: 'Maarten Lankhorst' <maarten.lankhorst at linux.intel.com>; Saarinen,
> Jani <jani.saarinen at intel.com>; intel-gfx at lists.freedesktop.org
> Cc: Kamath, Sunil <sunil.kamath at intel.com>
> Subject: RE: [PATCH v2 6/6] drm/i915: Do not do fb src adjustments for
> NV12
> 
> 
> 
> > -----Original Message-----
> > From: Maarten Lankhorst [mailto:maarten.lankhorst at linux.intel.com]
> > Sent: Tuesday, April 17, 2018 1:21 PM
> > To: Srinivas, Vidya <vidya.srinivas at intel.com>; Saarinen, Jani
> > <jani.saarinen at intel.com>; intel-gfx at lists.freedesktop.org
> > Cc: Kamath, Sunil <sunil.kamath at intel.com>
> > Subject: Re: [PATCH v2 6/6] drm/i915: Do not do fb src adjustments for
> > NV12
> >
> > Op 17-04-18 om 09:38 schreef Srinivas, Vidya:
> > >
> > >> -----Original Message-----
> > >> From: Maarten Lankhorst [mailto:maarten.lankhorst at linux.intel.com]
> > >> Sent: Tuesday, April 17, 2018 12:55 PM
> > >> To: Saarinen, Jani <jani.saarinen at intel.com>; Srinivas, Vidya
> > >> <vidya.srinivas at intel.com>; intel-gfx-trybot at lists.freedesktop.org;
> > >> intel- gfx at lists.freedesktop.org
> > >> Cc: Kamath, Sunil <sunil.kamath at intel.com>
> > >> Subject: Re: [PATCH v2 6/6] drm/i915: Do not do fb src adjustments
> > >> for
> > >> NV12
> > >>
> > >> Op 17-04-18 om 08:03 schreef Saarinen, Jani:
> > >>> Lets move this to intel-gfx to get more eyes on it.
> > >>>
> > >>>> -----Original Message-----
> > >>>> From: Srinivas, Vidya
> > >>>> Sent: tiistai 17. huhtikuuta 2018 5.47
> > >>>> To: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>;
> > >>>> intel-gfx- trybot at lists.freedesktop.org
> > >>>> Cc: Kamath, Sunil <sunil.kamath at intel.com>; Saarinen, Jani
> > >>>> <jani.saarinen at intel.com>
> > >>>> Subject: RE: [PATCH v2 6/6] drm/i915: Do not do fb src
> > >>>> adjustments for NV12
> > >>>>
> > >>>>
> > >>>>
> > >>>>> -----Original Message-----
> > >>>>> From: Maarten Lankhorst
> > >>>>> [mailto:maarten.lankhorst at linux.intel.com]
> > >>>>> Sent: Monday, April 16, 2018 8:00 PM
> > >>>>> To: Srinivas, Vidya <vidya.srinivas at intel.com>; intel-gfx-
> > >>>>> trybot at lists.freedesktop.org
> > >>>>> Cc: Kamath, Sunil <sunil.kamath at intel.com>; Saarinen, Jani
> > >>>>> <jani.saarinen at intel.com>
> > >>>>> Subject: Re: [PATCH v2 6/6] drm/i915: Do not do fb src
> > >>>>> adjustments for
> > >>>>> NV12
> > >>>>>
> > >>>>> Hmm, more thought about src adjustments...
> > >>>>>
> > >>>>> Op 13-04-18 om 07:22 schreef Vidya Srinivas:
> > >>>>>> We skip src trunction/adjustments for
> > >>>>>> NV12 case and handle the sizes directly.
> > >>>>>> Without this, pipe fifo underruns are seen on APL/KBL.
> > >>>>>>
> > >>>>>> v2: For NV12, making the src coordinates multiplier of 4
> > >>>>>>
> > >>>>>> Credits-to: Maarten Lankhorst
> > >>>>>> <maarten.lankhorst at linux.intel.com>
> > >>>>>> Signed-off-by: Vidya Srinivas <vidya.srinivas at intel.com>
> > >>>>>> ---
> > >>>>>>  drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++
> > >>>>>> drivers/gpu/drm/i915/intel_sprite.c  | 15 +++++++++++++++
> > >>>>>>  2 files changed, 26 insertions(+)
> > >>>>>>
> > >>>>>> diff --git a/drivers/gpu/drm/i915/intel_display.c
> > >>>>>> b/drivers/gpu/drm/i915/intel_display.c
> > >>>>>> index bc83f10..f64708f 100644
> > >>>>>> --- a/drivers/gpu/drm/i915/intel_display.c
> > >>>>>> +++ b/drivers/gpu/drm/i915/intel_display.c
> > >>>>>> @@ -12978,6 +12978,10 @@ intel_check_primary_plane(struct
> > >>>>> intel_plane *plane,
> > >>>>>>  	bool can_position = false;
> > >>>>>>  	int ret;
> > >>>>>>  	uint32_t pixel_format = 0;
> > >>>>>> +	struct drm_plane_state *plane_state = &state->base;
> > >>>>>> +	struct drm_rect *src = &plane_state->src;
> > >>>>>> +
> > >>>>>> +	*src = drm_plane_state_src(plane_state);
> > >>>>>>
> > >>>>>>  	if (INTEL_GEN(dev_priv) >= 9) {
> > >>>>>>  		/* use scaler when colorkey is not required */ @@ -
> > 13001,6
> > >>>>>> +13005,13 @@ intel_check_primary_plane(struct intel_plane
> > *plane,
> > >>>>>>  	if (!state->base.fb)
> > >>>>>>  		return 0;
> > >>>>>>
> > >>>>>> +	if (pixel_format == DRM_FORMAT_NV12) {
> > >>>>>> +		src->x1 = (((src->x1 >> 16)/4)*4) << 16;
> > >>>>>> +		src->x2 = (((src->x2 >> 16)/4)*4) << 16;
> > >>>>>> +		src->y1 = (((src->y1 >> 16)/4)*4) << 16;
> > >>>>>> +		src->y2 = (((src->y2 >> 16)/4)*4) << 16;
> > >>>>>> +	}
> > >>>>> Lets reject non multiple of 4 coordinates for plane_state's
> > >>>>> src_x and src_y, and before adjustment also reject non multiple
> > >>>>> of 4 src_w/src_h.fter that we can also reject clipping to the
> > >>>>> right/bottom edge of the screen, if the pipe_src_w/h is not a
> > >>>>> multiple of 4. That way an application trying to go beyond the
> screen.
> > >>>> kms_plane_scaling and some other tests during execution generate
> > >>>> lots of non mult of 4 buffer width/height. All these tests will
> > >>>> show fail in the IGT BAT.
> > >>>> In some cases, even thought the width and height will be multiple
> > >>>> of
> > >>>> 4 before the Adjustment (say our 16x16 buffer), this after
> > >>>> adjustment becomes a 15 in intel_check_sprite_plane.
> > >>>> This again would cause underrun. If we reject non multiple of 4s
> > >>>> in our skl_update_scaler also, then even simple tests with 16x16
> > >>>> like rotation will fail due to it getting adjusted.
> > >> Correct. This is why we fix up to a multiple of 4 after
> > >> adjustments, and reject user passed coordinates before adjustment..
> > >> plane_state->src_x/y/w/h is the property set by the user, while the
> > >> plane_state->src rect is set and fixed up in the kernel.
> > >>
> > >> Rejecting clipping with positive coordinates if pipe_src w/h is not
> > >> a multiple of 4 will fix a border case that shouldn't affect most
> > >> modes, where the plane wouldn't extend to the crtc borders, which
> > >> is
> > what userspace wants there.
> > >>
> > > Thank you. Oh okay. Sorry. I thought we just reject and not do the
> > > fixing
> > (mult of 4 later).
> > > Sure, I will change the patch to also reject the coordinates before
> > > adjustment (if its not Mult of 4).
> > >
> > >
> > This can be done in skl_check_plane_surface,
> > plane_state->src_{x,y,w,h} contains the user requested values.
> 
> Apologies for asking again. The adjustments are done in check_plane (both
> primary and sprite) And towards the end of check_plane we call the
> skl_check_plane_surface.
> I got your point that we will reject the user requested values if they are not
> multiple of 4.
> But before we reach skl_check_plane_surface, they would’ve been
> adjusted/clipped etc They wont remain user requested as is when they enter
> skl_check_plane_surface.
> Please correct me if I am wrong or I am missing in understanding something
> here :(
> 
> I can add the add conversion to multiple of 4 in skl_check_plane_surface but
> rejection should be done before the clipping/adjustment Or else, I move the
> entire clipping/adjustment code to skl_check_plane_surface?
> 

Sorry, I got it. You said, we don’t do adjustments in case of NV12 in sprite and move
The handling to skl_check_plane_surface. I will do the change and submit. Sorry.
Thank you.

> Regards
> Vidya
> >
> > ~Maarten