[PATCH 1/6] drm/i915: Align PLANE_SURF to 16k on ADL for async flips

[Murthy, Arun R]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville
> Syrjala
> Sent: Wednesday, March 20, 2024 9:34 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [PATCH 1/6] drm/i915: Align PLANE_SURF to 16k on ADL for async flips
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> On ADL async flips apparently generate DMAR and GGTT faults (with
> accompanying visual glitches) unless PLANE_SURF is aligned to at least 16k.
> Bump up the alignment to 16k.

I don’t find any such restriction in the spec. Can you please add link to the spec?

Thanks and Regards,
Arun R Murthy
-------------------
> 
> TODO: analyze things better to figure out what is really
>       going on here
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dpt.c    |  7 ++++---
>  drivers/gpu/drm/i915/display/intel_dpt.h    |  3 ++-
>  drivers/gpu/drm/i915/display/intel_fb.c     | 17 ++++++++++++++++-
>  drivers/gpu/drm/i915/display/intel_fb_pin.c | 10 +++++-----
>  4 files changed, 27 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dpt.c
> b/drivers/gpu/drm/i915/display/intel_dpt.c
> index b29bceff73f2..786d3f2e94c7 100644
> --- a/drivers/gpu/drm/i915/display/intel_dpt.c
> +++ b/drivers/gpu/drm/i915/display/intel_dpt.c
> @@ -121,7 +121,8 @@ static void dpt_cleanup(struct i915_address_space
> *vm)
>  	i915_gem_object_put(dpt->obj);
>  }
> 
> -struct i915_vma *intel_dpt_pin(struct i915_address_space *vm)
> +struct i915_vma *intel_dpt_pin(struct i915_address_space *vm,
> +			       unsigned int alignment)
>  {
>  	struct drm_i915_private *i915 = vm->i915;
>  	struct i915_dpt *dpt = i915_vm_to_dpt(vm); @@ -143,8 +144,8 @@
> struct i915_vma *intel_dpt_pin(struct i915_address_space *vm)
>  		if (err)
>  			continue;
> 
> -		vma = i915_gem_object_ggtt_pin_ww(dpt->obj, &ww, NULL, 0,
> 4096,
> -						  pin_flags);
> +		vma = i915_gem_object_ggtt_pin_ww(dpt->obj, &ww, NULL, 0,
> +						  alignment, pin_flags);
>  		if (IS_ERR(vma)) {
>  			err = PTR_ERR(vma);
>  			continue;
> diff --git a/drivers/gpu/drm/i915/display/intel_dpt.h
> b/drivers/gpu/drm/i915/display/intel_dpt.h
> index e18a9f767b11..f467578a4950 100644
> --- a/drivers/gpu/drm/i915/display/intel_dpt.h
> +++ b/drivers/gpu/drm/i915/display/intel_dpt.h
> @@ -13,7 +13,8 @@ struct i915_vma;
>  struct intel_framebuffer;
> 
>  void intel_dpt_destroy(struct i915_address_space *vm); -struct i915_vma
> *intel_dpt_pin(struct i915_address_space *vm);
> +struct i915_vma *intel_dpt_pin(struct i915_address_space *vm,
> +			       unsigned int alignment);
>  void intel_dpt_unpin(struct i915_address_space *vm);  void
> intel_dpt_suspend(struct drm_i915_private *i915);  void
> intel_dpt_resume(struct drm_i915_private *i915); diff --git
> a/drivers/gpu/drm/i915/display/intel_fb.c
> b/drivers/gpu/drm/i915/display/intel_fb.c
> index 3ea6470d6d92..58ead05fba6f 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb.c
> +++ b/drivers/gpu/drm/i915/display/intel_fb.c
> @@ -805,8 +805,23 @@ unsigned int intel_surf_alignment(const struct
> drm_framebuffer *fb,  {
>  	struct drm_i915_private *dev_priv = to_i915(fb->dev);
> 
> -	if (intel_fb_uses_dpt(fb))
> +	if (intel_fb_uses_dpt(fb)) {
> +		/* AUX_DIST needs only 4K alignment */
> +		if (intel_fb_is_ccs_aux_plane(fb, color_plane))
> +			return 512 * 4096;
> +
> +		/*
> +		 * FIXME ADL sees GGTT/DMAR faults with async
> +		 * flips unless we align to 16k at least.
> +		 * Figure out what's going on here...
> +		 */
> +		if (IS_ALDERLAKE_P(dev_priv) &&
> +		    !intel_fb_is_ccs_modifier(fb->modifier) &&
> +		    HAS_ASYNC_FLIPS(dev_priv))
> +			return 512 * 16 * 1024;
> +
>  		return 512 * 4096;
> +	}
> 
>  	/* AUX_DIST needs only 4K alignment */
>  	if (intel_fb_is_ccs_aux_plane(fb, color_plane)) diff --git
> a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> index 7b42aef37d2f..c28ae99ebe6a 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> @@ -19,6 +19,7 @@
>  static struct i915_vma *
>  intel_pin_fb_obj_dpt(struct drm_framebuffer *fb,
>  		     const struct i915_gtt_view *view,
> +		     unsigned int alignment,
>  		     bool uses_fence,
>  		     unsigned long *out_flags,
>  		     struct i915_address_space *vm)
> @@ -28,7 +29,6 @@ intel_pin_fb_obj_dpt(struct drm_framebuffer *fb,
>  	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
>  	struct i915_gem_ww_ctx ww;
>  	struct i915_vma *vma;
> -	u32 alignment;
>  	int ret;
> 
>  	/*
> @@ -41,8 +41,6 @@ intel_pin_fb_obj_dpt(struct drm_framebuffer *fb,
>  	if (WARN_ON(!i915_gem_object_is_framebuffer(obj)))
>  		return ERR_PTR(-EINVAL);
> 
> -	alignment = 4096 * 512;
> -
>  	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
> 
>  	for_i915_gem_ww(&ww, ret, true) {
> @@ -257,14 +255,16 @@ int intel_plane_pin_fb(struct intel_plane_state
> *plane_state)
>  		plane_state->ggtt_vma = vma;
>  	} else {
>  		struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
> +		unsigned int alignment = intel_surf_alignment(fb, 0);
> 
> -		vma = intel_dpt_pin(intel_fb->dpt_vm);
> +		vma = intel_dpt_pin(intel_fb->dpt_vm, alignment / 512);
>  		if (IS_ERR(vma))
>  			return PTR_ERR(vma);
> 
>  		plane_state->ggtt_vma = vma;
> 
> -		vma = intel_pin_fb_obj_dpt(fb, &plane_state->view.gtt, false,
> +		vma = intel_pin_fb_obj_dpt(fb, &plane_state->view.gtt,
> +					   alignment, false,
>  					   &plane_state->flags, intel_fb-
> >dpt_vm);
>  		if (IS_ERR(vma)) {
>  			intel_dpt_unpin(intel_fb->dpt_vm);
> --
> 2.43.2