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

[Maarten Lankhorst]

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.

~Maarten