Re: [PATCH v3 04/10] drm: Convert connector_helper_funcs->atomic_check to accept drm_atomic_state

[Sean Paul <sean@poorly.run>]

On Thu, May 16, 2019 at 03:00:01PM +0300, Laurent Pinchart wrote:
> Hi Sean,
> 
> On Mon, May 13, 2019 at 10:38:58AM -0400, Sean Paul wrote:
> > On Sat, May 11, 2019 at 3:12 PM Laurent Pinchart wrote:
> > > On Thu, May 02, 2019 at 03:49:46PM -0400, Sean Paul wrote:
> > >> From: Sean Paul <seanpaul@chromium.org>
> > >>
> > >> Everyone who implements connector_helper_funcs->atomic_check reaches
> > >> into the connector state to get the atomic state. Instead of continuing
> > >> this pattern, change the callback signature to just give atomic state
> > >> and let the driver determine what it does and does not need from it.
> > >>
> > >> Eventually all atomic functions should do this, but that's just too much
> > >> busy work for me.
> > >
> > > Given that drivers also access the connector state, isn't this slightly
> > > more inefficient ?
> > 
> > Inefficient in terms of what?
> 
> In terms of the operation having to lookup the connector state, when the
> caller has it and can easily pass it. As Daniel commented, this may be
> the price to pay for a cleaner API, but I wonder how much overhead all
> the state tracking is costing.
> 

It'd be interesting to quantify, but iirc the last time we benchmarked
atomic check commits they were virtually free (~thousands/s).

> > Agree that in isolation this patch might seem unnecessary, but it ties
> > in with the encoder and bridge CLs which accept drm_atomic_state in
> 
> CLs ?

Googleism for patches, I usually catch these before sending... guess I missed
one.

Sean

> 
> > their hooks. In general the idea is to convert all atomic functions to
> > take overall atomic state instead of just their object state. Reality
> > has proven to be more complicated and we need more access than what
> > the current implementation provides.
> > 
> > Sean
> > 
> > >> Changes in v3:
> > >> - Added to the set
> > >>
> > >> Cc: Daniel Vetter <daniel@ffwll.ch>
> > >> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > >> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> > >> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> > >> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > >> Cc: Ben Skeggs <bskeggs@redhat.com>
> > >> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > >> Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> > >> Cc: Eric Anholt <eric@anholt.net>
> > >> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > >> ---
> > >>  drivers/gpu/drm/drm_atomic_helper.c      |  4 ++--
> > >>  drivers/gpu/drm/i915/intel_atomic.c      |  8 +++++---
> > >>  drivers/gpu/drm/i915/intel_dp_mst.c      |  7 ++++---
> > >>  drivers/gpu/drm/i915/intel_drv.h         |  2 +-
> > >>  drivers/gpu/drm/i915/intel_sdvo.c        |  9 +++++----
> > >>  drivers/gpu/drm/i915/intel_tv.c          |  8 +++++---
> > >>  drivers/gpu/drm/nouveau/dispnv50/disp.c  |  5 +++--
> > >>  drivers/gpu/drm/rcar-du/rcar_lvds.c      | 12 +++++++-----
> > >>  drivers/gpu/drm/vc4/vc4_txp.c            |  7 ++++---
> > >>  include/drm/drm_modeset_helper_vtables.h |  2 +-
> > >>  10 files changed, 37 insertions(+), 27 deletions(-)
> > >>
> > >> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > >> index 9d9e47276839..fa5a367507c1 100644
> > >> --- a/drivers/gpu/drm/drm_atomic_helper.c
> > >> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > >> @@ -683,7 +683,7 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
> > >>               }
> > >>
> > >>               if (funcs->atomic_check)
> > >> -                     ret = funcs->atomic_check(connector, new_connector_state);
> > >> +                     ret = funcs->atomic_check(connector, state);
> > >>               if (ret)
> > >>                       return ret;
> > >>
> > >> @@ -725,7 +725,7 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
> > >>                       continue;
> > >>
> > >>               if (funcs->atomic_check)
> > >> -                     ret = funcs->atomic_check(connector, new_connector_state);
> > >> +                     ret = funcs->atomic_check(connector, state);
> > >>               if (ret)
> > >>                       return ret;
> > >>       }
> > >> diff --git a/drivers/gpu/drm/i915/intel_atomic.c b/drivers/gpu/drm/i915/intel_atomic.c
> > >> index b844e8840c6f..e8a5b82e9242 100644
> > >> --- a/drivers/gpu/drm/i915/intel_atomic.c
> > >> +++ b/drivers/gpu/drm/i915/intel_atomic.c
> > >> @@ -103,12 +103,14 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
> > >>  }
> > >>
> > >>  int intel_digital_connector_atomic_check(struct drm_connector *conn,
> > >> -                                      struct drm_connector_state *new_state)
> > >> +                                      struct drm_atomic_state *state)
> > >>  {
> > >> +     struct drm_connector_state *new_state =
> > >> +             drm_atomic_get_new_connector_state(state, conn);
> > >>       struct intel_digital_connector_state *new_conn_state =
> > >>               to_intel_digital_connector_state(new_state);
> > >>       struct drm_connector_state *old_state =
> > >> -             drm_atomic_get_old_connector_state(new_state->state, conn);
> > >> +             drm_atomic_get_old_connector_state(state, conn);
> > >>       struct intel_digital_connector_state *old_conn_state =
> > >>               to_intel_digital_connector_state(old_state);
> > >>       struct drm_crtc_state *crtc_state;
> > >> @@ -118,7 +120,7 @@ int intel_digital_connector_atomic_check(struct drm_connector *conn,
> > >>       if (!new_state->crtc)
> > >>               return 0;
> > >>
> > >> -     crtc_state = drm_atomic_get_new_crtc_state(new_state->state, new_state->crtc);
> > >> +     crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
> > >>
> > >>       /*
> > >>        * These properties are handled by fastset, and might not end
> > >> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> > >> index 19d81cef2ab6..89cfec128ba0 100644
> > >> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> > >> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> > >> @@ -143,9 +143,10 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> > >>
> > >>  static int
> > >>  intel_dp_mst_atomic_check(struct drm_connector *connector,
> > >> -                       struct drm_connector_state *new_conn_state)
> > >> +                       struct drm_atomic_state *state)
> > >>  {
> > >> -     struct drm_atomic_state *state = new_conn_state->state;
> > >> +     struct drm_connector_state *new_conn_state =
> > >> +             drm_atomic_get_new_connector_state(state, connector);
> > >>       struct drm_connector_state *old_conn_state =
> > >>               drm_atomic_get_old_connector_state(state, connector);
> > >>       struct intel_connector *intel_connector =
> > >> @@ -155,7 +156,7 @@ intel_dp_mst_atomic_check(struct drm_connector *connector,
> > >>       struct drm_dp_mst_topology_mgr *mgr;
> > >>       int ret;
> > >>
> > >> -     ret = intel_digital_connector_atomic_check(connector, new_conn_state);
> > >> +     ret = intel_digital_connector_atomic_check(connector, state);
> > >>       if (ret)
> > >>               return ret;
> > >>
> > >> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > >> index f8c7b291fdc3..88571b8e8d62 100644
> > >> --- a/drivers/gpu/drm/i915/intel_drv.h
> > >> +++ b/drivers/gpu/drm/i915/intel_drv.h
> > >> @@ -2481,7 +2481,7 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
> > >>                                               struct drm_property *property,
> > >>                                               u64 val);
> > >>  int intel_digital_connector_atomic_check(struct drm_connector *conn,
> > >> -                                      struct drm_connector_state *new_state);
> > >> +                                      struct drm_atomic_state *state);
> > >>  struct drm_connector_state *
> > >>  intel_digital_connector_duplicate_state(struct drm_connector *connector);
> > >>
> > >> diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> > >> index 68f497493d43..72ea164b971c 100644
> > >> --- a/drivers/gpu/drm/i915/intel_sdvo.c
> > >> +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> > >> @@ -2342,9 +2342,10 @@ static const struct drm_connector_funcs intel_sdvo_connector_funcs = {
> > >>  };
> > >>
> > >>  static int intel_sdvo_atomic_check(struct drm_connector *conn,
> > >> -                                struct drm_connector_state *new_conn_state)
> > >> +                                struct drm_atomic_state *state)
> > >>  {
> > >> -     struct drm_atomic_state *state = new_conn_state->state;
> > >> +     struct drm_connector_state *new_conn_state =
> > >> +             drm_atomic_get_new_connector_state(state, conn);
> > >>       struct drm_connector_state *old_conn_state =
> > >>               drm_atomic_get_old_connector_state(state, conn);
> > >>       struct intel_sdvo_connector_state *old_state =
> > >> @@ -2356,13 +2357,13 @@ static int intel_sdvo_atomic_check(struct drm_connector *conn,
> > >>           (memcmp(&old_state->tv, &new_state->tv, sizeof(old_state->tv)) ||
> > >>            memcmp(&old_conn_state->tv, &new_conn_state->tv, sizeof(old_conn_state->tv)))) {
> > >>               struct drm_crtc_state *crtc_state =
> > >> -                     drm_atomic_get_new_crtc_state(new_conn_state->state,
> > >> +                     drm_atomic_get_new_crtc_state(state,
> > >>                                                     new_conn_state->crtc);
> > >>
> > >>               crtc_state->connectors_changed = true;
> > >>       }
> > >>
> > >> -     return intel_digital_connector_atomic_check(conn, new_conn_state);
> > >> +     return intel_digital_connector_atomic_check(conn, state);
> > >>  }
> > >>
> > >>  static const struct drm_connector_helper_funcs intel_sdvo_connector_helper_funcs = {
> > >> diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
> > >> index 3924c4944e1f..a41c5b467c14 100644
> > >> --- a/drivers/gpu/drm/i915/intel_tv.c
> > >> +++ b/drivers/gpu/drm/i915/intel_tv.c
> > >> @@ -1817,16 +1817,18 @@ static const struct drm_connector_funcs intel_tv_connector_funcs = {
> > >>  };
> > >>
> > >>  static int intel_tv_atomic_check(struct drm_connector *connector,
> > >> -                              struct drm_connector_state *new_state)
> > >> +                              struct drm_atomic_state *state)
> > >>  {
> > >> +     struct drm_connector_state *new_state;
> > >>       struct drm_crtc_state *new_crtc_state;
> > >>       struct drm_connector_state *old_state;
> > >>
> > >> +     new_state = drm_atomic_get_new_connector_state(state, connector);
> > >>       if (!new_state->crtc)
> > >>               return 0;
> > >>
> > >> -     old_state = drm_atomic_get_old_connector_state(new_state->state, connector);
> > >> -     new_crtc_state = drm_atomic_get_new_crtc_state(new_state->state, new_state->crtc);
> > >> +     old_state = drm_atomic_get_old_connector_state(state, connector);
> > >> +     new_crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
> > >>
> > >>       if (old_state->tv.mode != new_state->tv.mode ||
> > >>           old_state->tv.margins.left != new_state->tv.margins.left ||
> > >> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > >> index 4b1650f51955..7ba373f493b2 100644
> > >> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > >> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > >> @@ -948,11 +948,12 @@ nv50_mstc_get_modes(struct drm_connector *connector)
> > >>
> > >>  static int
> > >>  nv50_mstc_atomic_check(struct drm_connector *connector,
> > >> -                    struct drm_connector_state *new_conn_state)
> > >> +                    struct drm_atomic_state *state)
> > >>  {
> > >> -     struct drm_atomic_state *state = new_conn_state->state;
> > >>       struct nv50_mstc *mstc = nv50_mstc(connector);
> > >>       struct drm_dp_mst_topology_mgr *mgr = &mstc->mstm->mgr;
> > >> +     struct drm_connector_state *new_conn_state =
> > >> +             drm_atomic_get_new_connector_state(state, connector);
> > >>       struct drm_connector_state *old_conn_state =
> > >>               drm_atomic_get_old_connector_state(state, connector);
> > >>       struct drm_crtc_state *crtc_state;
> > >> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > >> index 620b51aab291..5b81ba2a7f27 100644
> > >> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > >> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > >> @@ -92,13 +92,15 @@ static int rcar_lvds_connector_get_modes(struct drm_connector *connector)
> > >>  }
> > >>
> > >>  static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
> > >> -                                         struct drm_connector_state *state)
> > >> +                                         struct drm_atomic_state *state)
> > >>  {
> > >>       struct rcar_lvds *lvds = connector_to_rcar_lvds(connector);
> > >>       const struct drm_display_mode *panel_mode;
> > >> +     struct drm_connector_state *conn_state;
> > >>       struct drm_crtc_state *crtc_state;
> > >>
> > >> -     if (!state->crtc)
> > >> +     conn_state = drm_atomic_get_new_connector_state(state, connector);
> > >> +     if (!conn_state->crtc)
> > >>               return 0;
> > >>
> > >>       if (list_empty(&connector->modes)) {
> > >> @@ -110,9 +112,9 @@ static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
> > >>                                     struct drm_display_mode, head);
> > >>
> > >>       /* We're not allowed to modify the resolution. */
> > >> -     crtc_state = drm_atomic_get_crtc_state(state->state, state->crtc);
> > >> -     if (IS_ERR(crtc_state))
> > >> -             return PTR_ERR(crtc_state);
> > >> +     crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
> > >> +     if (!crtc_state)
> > >> +             return -EINVAL;
> > >>
> > >>       if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
> > >>           crtc_state->mode.vdisplay != panel_mode->vdisplay)
> > >> diff --git a/drivers/gpu/drm/vc4/vc4_txp.c b/drivers/gpu/drm/vc4/vc4_txp.c
> > >> index c8b89a78f9f4..96f91c1b4b6e 100644
> > >> --- a/drivers/gpu/drm/vc4/vc4_txp.c
> > >> +++ b/drivers/gpu/drm/vc4/vc4_txp.c
> > >> @@ -221,17 +221,18 @@ static const u32 txp_fmts[] = {
> > >>  };
> > >>
> > >>  static int vc4_txp_connector_atomic_check(struct drm_connector *conn,
> > >> -                                     struct drm_connector_state *conn_state)
> > >> +                                       struct drm_atomic_state *state)
> > >>  {
> > >> +     struct drm_connector_state *conn_state;
> > >>       struct drm_crtc_state *crtc_state;
> > >>       struct drm_framebuffer *fb;
> > >>       int i;
> > >>
> > >> +     conn_state = drm_atomic_get_new_connector_state(state, conn);
> > >>       if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
> > >>               return 0;
> > >>
> > >> -     crtc_state = drm_atomic_get_new_crtc_state(conn_state->state,
> > >> -                                                conn_state->crtc);
> > >> +     crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);
> > >>
> > >>       fb = conn_state->writeback_job->fb;
> > >>       if (fb->width != crtc_state->mode.hdisplay ||
> > >> diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
> > >> index de57fb40cb6e..adc8b7cf64b5 100644
> > >> --- a/include/drm/drm_modeset_helper_vtables.h
> > >> +++ b/include/drm/drm_modeset_helper_vtables.h
> > >> @@ -1020,7 +1020,7 @@ struct drm_connector_helper_funcs {
> > >>        * deadlock.
> > >>        */
> > >>       int (*atomic_check)(struct drm_connector *connector,
> > >> -                         struct drm_connector_state *state);
> > >> +                         struct drm_atomic_state *state);
> > >>
> > >>       /**
> > >>        * @atomic_commit:
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Sean Paul, Software Engineer, Google / Chromium OS