Message-ID: <20191009051517.GA30868@jamwan02-TSP300>
Date:   Wed, 9 Oct 2019 05:15:24 +0000
From:   "james qian wang (Arm Technology China)" <james.qian.wang@....com>
To:     Daniel Vetter <daniel@...ll.ch>
CC:     "Lowry Li (Arm Technology China)" <Lowry.Li@....com>,
        Liviu Dudau <Liviu.Dudau@....com>,
        "maarten.lankhorst@...ux.intel.com" 
        <maarten.lankhorst@...ux.intel.com>,
        "seanpaul@...omium.org" <seanpaul@...omium.org>,
        "airlied@...ux.ie" <airlied@...ux.ie>,
        Brian Starkey <Brian.Starkey@....com>,
        Ayan Halder <Ayan.Halder@....com>,
        "Jonathan Chai (Arm Technology China)" <Jonathan.Chai@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "Julien Yin (Arm Technology China)" <Julien.Yin@....com>,
        nd <nd@....com>
Subject: Re: [PATCH] drm/komeda: Adds zorder support

On Tue, Oct 08, 2019 at 05:00:46PM +0200, Daniel Vetter wrote:
> On Mon, May 20, 2019 at 5:33 AM Lowry Li (Arm Technology China)
> <Lowry.Li@....com> wrote:
> >
> > - Creates the zpos property.
> > - Implement komeda_crtc_normalize_zpos to replace
> > drm_atomic_normalize_zpos, reasons as the following:
> >
> > 1. The drm_atomic_normalize_zpos allows to configure same zpos for
> > different planes, but komeda doesn't support such configuration.
> 
> Just stumbled over your custom normalized_zpos calculation, and it
> looks very fishy. You seem to reinvent the normalized zpos
> computation, which has the entire job of resolving duplicated zpos
> values (which can happen with legacy kms). So the above is definitely
> wrong.
> 
> Can you pls do a patch to remove your own code, and replace it with
> helper usage? Or at least explain why exactly you can't use the
> standard normalized zpos stuff and need your own (since it really
> looks like just reinventing the same thing).
> -Daniel
> 
> > 2. For further slave pipline case, Komeda need to calculate the
> > max_slave_zorder, we will merge such calculation into
> > komed_crtc_normalize_zpos to save a separated plane_state loop.

> > 3. For feature none-scaling layer_split, which a plane_state will be
> > assigned to two individual layers(left/right), which requires two
> > normalize_zpos for this plane, plane_st->normalize_zpos will be used
> > by left layer, normalize_zpos + 1 for right_layer.
> >

Yes, the komeda/drm zpos_normalize are simlilar, 

First requirement is here the "layer split" support.

Komeda HW has a input size limitation for YUV format, compare with
RGB, which only has the half capablities, like

- Layer support 4K RGB input size.
- YUV only can support 2K.

To hide this limitation, we introdue Layer split, which splits
one drm_plane data flows to two halves (left/right), and handle them by
two individual HW layers, and of course, two layers need two different
normalize_zpos. but drm_atomic_normalize_zpos() only assign one value
to this plane, but we need two values for layer_split.

Secondary requirement:

we also need the ordered plane list that built by normalize_zpos(),
but current drm version doesn't return it.

For more komeda things:
https://www.kernel.org/doc/html/latest/gpu/komeda-kms.html?highlight=komeda

LAST.
Yes, the komeda and drm version zpos normalize are similar,
we can not use the standard version only because some tiny but
special requirements.
I saw the upstream is working for the zorder refinement, maybe we
can add komeda's requirements into the drm_atomic_normalize_zpos()
and drop komeda version together with this refinement.

Best Regards
James

> > This patch series depends on:
> > - https://patchwork.freedesktop.org/series/58710/
> > - https://patchwork.freedesktop.org/series/59000/
> > - https://patchwork.freedesktop.org/series/59002/
> > - https://patchwork.freedesktop.org/series/59747/
> > - https://patchwork.freedesktop.org/series/59915/
> > - https://patchwork.freedesktop.org/series/60083/
> > - https://patchwork.freedesktop.org/series/60698/
> >
> > Signed-off-by: Lowry Li (Arm Technology China) <lowry.li@....com>
> > ---
> >  drivers/gpu/drm/arm/display/komeda/komeda_kms.c   | 90 ++++++++++++++++++++++-
> >  drivers/gpu/drm/arm/display/komeda/komeda_kms.h   |  3 +
> >  drivers/gpu/drm/arm/display/komeda/komeda_plane.c |  6 +-
> >  3 files changed, 97 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > index 306ea06..0ec7665 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > @@ -100,6 +100,90 @@ static void komeda_kms_commit_tail(struct drm_atomic_state *old_state)
> >         .atomic_commit_tail = komeda_kms_commit_tail,
> >  };
> >
> > +static int komeda_plane_state_list_add(struct drm_plane_state *plane_st,
> > +                                      struct list_head *zorder_list)
> > +{
> > +       struct komeda_plane_state *new = to_kplane_st(plane_st);
> > +       struct komeda_plane_state *node, *last;
> > +
> > +       last = list_empty(zorder_list) ?
> > +              NULL : list_last_entry(zorder_list, typeof(*last), zlist_node);
> > +
> > +       /* Considering the list sequence is zpos increasing, so if list is empty
> > +        * or the zpos of new node bigger than the last node in list, no need
> > +        * loop and just insert the new one to the tail of the list.
> > +        */
> > +       if (!last || (new->base.zpos > last->base.zpos)) {
> > +               list_add_tail(&new->zlist_node, zorder_list);
> > +               return 0;
> > +       }
> > +
> > +       /* Build the list by zpos increasing */
> > +       list_for_each_entry(node, zorder_list, zlist_node) {
> > +               if (new->base.zpos < node->base.zpos) {
> > +                       list_add_tail(&new->zlist_node, &node->zlist_node);
> > +                       break;
> > +               } else if (node->base.zpos == new->base.zpos) {
> > +                       struct drm_plane *a = node->base.plane;
> > +                       struct drm_plane *b = new->base.plane;
> > +
> > +                       /* Komeda doesn't support setting a same zpos for
> > +                        * different planes.
> > +                        */
> > +                       DRM_DEBUG_ATOMIC("PLANE: %s and PLANE: %s are configured same zpos: %d.\n",
> > +                                        a->name, b->name, node->base.zpos);
> > +                       return -EINVAL;
> > +               }
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int komeda_crtc_normalize_zpos(struct drm_crtc *crtc,
> > +                                     struct drm_crtc_state *crtc_st)
> > +{
> > +       struct drm_atomic_state *state = crtc_st->state;
> > +       struct komeda_plane_state *kplane_st;
> > +       struct drm_plane_state *plane_st;
> > +       struct drm_framebuffer *fb;
> > +       struct drm_plane *plane;
> > +       struct list_head zorder_list;
> > +       int order = 0, err;
> > +
> > +       DRM_DEBUG_ATOMIC("[CRTC:%d:%s] calculating normalized zpos values\n",
> > +                        crtc->base.id, crtc->name);
> > +
> > +       INIT_LIST_HEAD(&zorder_list);
> > +
> > +       /* This loop also added all effected planes into the new state */
> > +       drm_for_each_plane_mask(plane, crtc->dev, crtc_st->plane_mask) {
> > +               plane_st = drm_atomic_get_plane_state(state, plane);
> > +               if (IS_ERR(plane_st))
> > +                       return PTR_ERR(plane_st);
> > +
> > +               /* Build a list by zpos increasing */
> > +               err = komeda_plane_state_list_add(plane_st, &zorder_list);
> > +               if (err)
> > +                       return err;
> > +       }
> > +
> > +       list_for_each_entry(kplane_st, &zorder_list, zlist_node) {
> > +               plane_st = &kplane_st->base;
> > +               fb = plane_st->fb;
> > +               plane = plane_st->plane;
> > +
> > +               plane_st->normalized_zpos = order++;
> > +
> > +               DRM_DEBUG_ATOMIC("[PLANE:%d:%s] zpos:%d, normalized zpos: %d\n",
> > +                                plane->base.id, plane->name,
> > +                                plane_st->zpos, plane_st->normalized_zpos);
> > +       }
> > +
> > +       crtc_st->zpos_changed = true;
> > +
> > +       return 0;
> > +}
> > +
> >  static int komeda_kms_check(struct drm_device *dev,
> >                             struct drm_atomic_state *state)
> >  {
> > @@ -111,7 +195,7 @@ static int komeda_kms_check(struct drm_device *dev,
> >         if (err)
> >                 return err;
> >
> > -       /* komeda need to re-calculate resource assumption in every commit
> > +       /* Komeda need to re-calculate resource assumption in every commit
> >          * so need to add all affected_planes (even unchanged) to
> >          * drm_atomic_state.
> >          */
> > @@ -119,6 +203,10 @@ static int komeda_kms_check(struct drm_device *dev,
> >                 err = drm_atomic_add_affected_planes(state, crtc);
> >                 if (err)
> >                         return err;
> > +
> > +               err = komeda_crtc_normalize_zpos(crtc, new_crtc_st);
> > +               if (err)
> > +                       return err;
> >         }
> >
> >         err = drm_atomic_helper_check_planes(dev, state);
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > index 178bee6..d1cef46 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > @@ -7,6 +7,7 @@
> >  #ifndef _KOMEDA_KMS_H_
> >  #define _KOMEDA_KMS_H_
> >
> > +#include <linux/list.h>
> >  #include <drm/drm_atomic.h>
> >  #include <drm/drm_atomic_helper.h>
> >  #include <drm/drm_crtc_helper.h>
> > @@ -46,6 +47,8 @@ struct komeda_plane {
> >  struct komeda_plane_state {
> >         /** @base: &drm_plane_state */
> >         struct drm_plane_state base;
> > +       /** @zlist_node: zorder list node */
> > +       struct list_head zlist_node;
> >
> >         /* @img_enhancement: on/off image enhancement */
> >         u8 img_enhancement : 1;
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> > index bcf30a7..aad7663 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> > @@ -21,7 +21,7 @@
> >
> >         memset(dflow, 0, sizeof(*dflow));
> >
> > -       dflow->blending_zorder = st->zpos;
> > +       dflow->blending_zorder = st->normalized_zpos;
> >
> >         /* if format doesn't have alpha, fix blend mode to PIXEL_NONE */
> >         dflow->pixel_blend_mode = fb->format->has_alpha ?
> > @@ -343,6 +343,10 @@ static int komeda_plane_add(struct komeda_kms_dev *kms,
> >         if (err)
> >                 goto cleanup;
> >
> > +       err = drm_plane_create_zpos_property(plane, layer->base.id, 0, 8);
> > +       if (err)
> > +               goto cleanup;
> > +
> >         return 0;
> >  cleanup:
> >         komeda_plane_destroy(plane);
> > --
> > 1.9.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@...ts.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch

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