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

["Srinivas, Vidya" <vidya.srinivas@intel.com>]

> -----Original Message-----
> From: Saarinen, Jani
> Sent: Tuesday, April 17, 2018 4:23 PM
> To: Srinivas, Vidya <vidya.srinivas@intel.com>; Maarten Lankhorst
> <maarten.lankhorst@linux.intel.com>; intel-gfx@lists.freedesktop.org
> Cc: Kamath, Sunil <sunil.kamath@intel.com>
> Subject: RE: [PATCH v2 6/6] drm/i915: Do not do fb src adjustments for
> NV12
> 
> HI,
> > -----Original Message-----
> > From: Srinivas, Vidya
> > Sent: tiistai 17. huhtikuuta 2018 13.49
> > To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>; Saarinen,
> > Jani <jani.saarinen@intel.com>; intel-gfx@lists.freedesktop.org
> > Cc: Kamath, Sunil <sunil.kamath@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@linux.intel.com]
> > > Sent: Tuesday, April 17, 2018 3:32 PM
> > > To: Srinivas, Vidya <vidya.srinivas@intel.com>; Saarinen, Jani
> > > <jani.saarinen@intel.com>; intel-gfx@lists.freedesktop.org
> > > Cc: Kamath, Sunil <sunil.kamath@intel.com>
> > > Subject: Re: [PATCH v2 6/6] drm/i915: Do not do fb src adjustments
> > > for
> > > NV12
> > >
> > > Op 17-04-18 om 11:42 schreef Srinivas, Vidya:
> > > >
> > > >> -----Original Message-----
> > > >> From: Maarten Lankhorst
> > > >> [mailto:maarten.lankhorst@linux.intel.com]
> > > >> Sent: Tuesday, April 17, 2018 3:04 PM
> > > >> To: Srinivas, Vidya <vidya.srinivas@intel.com>; Saarinen, Jani
> > > >> <jani.saarinen@intel.com>; intel-gfx@lists.freedesktop.org
> > > >> Cc: Kamath, Sunil <sunil.kamath@intel.com>
> > > >> Subject: Re: [PATCH v2 6/6] drm/i915: Do not do fb src
> > > >> adjustments for
> > > >> NV12
> > > >>
> > > >> Op 17-04-18 om 10:09 schreef Srinivas, Vidya:
> > > >>>> -----Original Message-----
> > > >>>> From: Srinivas, Vidya
> > > >>>> Sent: Tuesday, April 17, 2018 1:32 PM
> > > >>>> To: 'Maarten Lankhorst' <maarten.lankhorst@linux.intel.com>;
> > > >>>> Saarinen, Jani <jani.saarinen@intel.com>;
> > > >>>> intel-gfx@lists.freedesktop.org
> > > >>>> Cc: Kamath, Sunil <sunil.kamath@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@linux.intel.com]
> > > >>>>> Sent: Tuesday, April 17, 2018 1:21 PM
> > > >>>>> To: Srinivas, Vidya <vidya.srinivas@intel.com>; Saarinen, Jani
> > > >>>>> <jani.saarinen@intel.com>; intel-gfx@lists.freedesktop.org
> > > >>>>> Cc: Kamath, Sunil <sunil.kamath@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@linux.intel.com]
> > > >>>>>>> Sent: Tuesday, April 17, 2018 12:55 PM
> > > >>>>>>> To: Saarinen, Jani <jani.saarinen@intel.com>; Srinivas,
> > > >>>>>>> Vidya <vidya.srinivas@intel.com>;
> > > >>>>>>> intel-gfx-trybot@lists.freedesktop.org;
> > > >>>>>>> intel- gfx@lists.freedesktop.org
> > > >>>>>>> Cc: Kamath, Sunil <sunil.kamath@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@linux.intel.com>;
> > > >>>>>>>>> intel-gfx- trybot@lists.freedesktop.org
> > > >>>>>>>>> Cc: Kamath, Sunil <sunil.kamath@intel.com>; Saarinen, Jani
> > > >>>>>>>>> <jani.saarinen@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@linux.intel.com]
> > > >>>>>>>>>> Sent: Monday, April 16, 2018 8:00 PM
> > > >>>>>>>>>> To: Srinivas, Vidya <vidya.srinivas@intel.com>;
> > > >>>>>>>>>> intel-gfx- trybot@lists.freedesktop.org
> > > >>>>>>>>>> Cc: Kamath, Sunil <sunil.kamath@intel.com>; Saarinen,
> > > >>>>>>>>>> Jani <jani.saarinen@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@linux.intel.com>
> > > >>>>>>>>>>> Signed-off-by: Vidya Srinivas <vidya.srinivas@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.
> > > >>>
> > > >> Something like below? Untested..
> > > >> We should probably also restrict NV12 fb creation to not allow
> > > >> CCS
> > > formats.
> >
> > Thank you so much. Have submitted the changes to trybot
> > https://patchwork.freedesktop.org/series/41532/
> > PS: fb creation to not allow CCS - not done in this series
> Why not directly to intel-gfx?
Sure, I thought I had to send to trybot first. Will send it today.

Thanks
Vidya
> 
> 
> >
> > Regards
> > Vidya
> >
> > > >>
> > > >> ~Maarten
> > > >>
> > > >> diff --git a/drivers/gpu/drm/i915/intel_display.c
> > > >> b/drivers/gpu/drm/i915/intel_display.c
> > > >> index 4b3735720fee..c5da30c7ad04 100644
> > > >> --- a/drivers/gpu/drm/i915/intel_display.c
> > > >> +++ b/drivers/gpu/drm/i915/intel_display.c
> > > >> @@ -3090,6 +3090,38 @@ static int skl_check_main_surface(const
> > > struct
> > > >> intel_crtc_state *crtc_state,
> > > >>  	return 0;
> > > >>  }
> > > >>
> > > >> +static int skl_check_nv12_surface(const struct intel_crtc_state
> > > *crtc_state,
> > > >> +				  struct intel_plane_state
> *plane_state) {
> > > >> +	int crtc_x2 = plane_state->base.crtc_x + plane_state-
> >base.crtc_w;
> > > >> +	int crtc_y2 = plane_state->base.crtc_y +
> > > >> +plane_state->base.crtc_h;
> > > >> +
> > > >> +	/* Are the unadjusted coordinates passed in valid? */
> > > >> +	if ((plane_state->base.src_x >> 16) % 4 ||
> > > >> +	    (plane_state->base.src_y >> 16) % 4 ||
> > > >> +	    (plane_state->base.src_w >> 16) % 4 ||
> > > >> +	    (plane_state->base.src_h >> 16) % 4) {
> > > >> +		DRM_DEBUG_KMS("Source coordinates must be a
> multiple
> > > >> of 4 for NV12\n");
> > > >> +		return -EINVAL;
> > > >> +	}
> > > >> +
> > > >> +	/* Clipping would cause a 1-3 pixel gap at the edge of the
> screen? */
> > > >> +	if ((crtc_x2 > crtc_state->pipe_src_w && crtc_state-
> >pipe_src_w
> > > >> +%
> > > >> 4) ||
> > > >> +	    (crtc_y2 > crtc_state->pipe_src_h && crtc_state-
> >pipe_src_h
> > > >> +%
> > > >> +4))
> > > >> {
> > > >> +		DRM_DEBUG_KMS("It's not possible to clip %u,%u
> to
> > > >> %u,%u\n",
> > > >> +			      crtc_x2, crtc_y2,
> > > >> +			      crtc_state->pipe_src_w, crtc_state-
> >pipe_src_h);
> > > >> +		return -EINVAL;
> > > >> +	}
> > > >> +
> > > >> +	/* Make adjusted src coordinates a multiple of 4. */
> > > >> +	plane_state->base.src.x1 =
> DIV_ROUND_CLOSEST(plane_state-
> > > >>> base.src.x1, 1 << 18) << 18;
> > > >> +	plane_state->base.src.y1 =
> DIV_ROUND_CLOSEST(plane_state-
> > > >>> base.src.y1, 1 << 18) << 18;
> > > >> +	plane_state->base.src.x2 =
> DIV_ROUND_CLOSEST(plane_state-
> > > >>> base.src.x2, 1 << 18) << 18;
> > > >> +	plane_state->base.src.y2 =
> DIV_ROUND_CLOSEST(plane_state-
> > > >>> base.src.y2, 1 << 18) << 18;
> > > >> +	return 0;
> > > >> +}
> > > >> +
> > > > Thank you so much :) Only one problem. The primary plane clipping
> > > > happens inside the drm layer in
> > > > drm_atomic_helper_check_plane_state
> > > > So, clipping-clamping test passes coordinates 0, 257, 0, 159 to
> > > check_plane.
> > > > And there before adjusting we reject. So for primary alone, can I
> > > > retain the make multiple of 4 code in primary itself?
> > >
> > > The clipping affects plane_state->src.{x1, y1, x2, y2}, not
> > > plane_state-
> > > >src_{x,y,w,h}.
> > > They're different. The last set of coordinates will not be rotated
> > > or anything, the first set of coordinates are what we end up
> > > programming into the hardware. The patch I put above should be
> > > correctly rounding to a multiple of 4. :)
> > >
> > > ~Maarten

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