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

From: Daniel Vetter
Date: Mon May 13 2019 - 10:49:28 EST

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In reply to: Sean Paul: "Re: [PATCH v3 04/10] drm: Convert connector_helper_funcs->atomic_check to accept drm_atomic_state"
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On Sat, May 11, 2019 at 10:12:02PM +0300, Laurent Pinchart wrote:
> Hi Sean,
>
> Thank you for the patch.
>
> On Thu, May 02, 2019 at 03:49:46PM -0400, Sean Paul wrote:
> > From: Sean Paul <seanpaul@xxxxxxxxxxxx>
> >
> > 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 ?

It's atomic code, we're trying to optimize for clean code at the expense
of a bit of runtime overhead due to more pointer chasing. And I agree with
the general push, the pile of old/new_state pointers of various objects
we're passing around is confusing. Passing the overall drm_atomic_state
seems much more reasonable, and with that we can get everything else. Plus
it's much more obvious whether you have the old/new state (since that's
explicit when you look it up from the drm_atomic_state).

If we ever see this show up in profile, and it starts mattering, first
thing we need is a hashtable I think (atm it's list walking, which is just
terrible). But thus far no one cares.
-Daniel

>
> > Changes in v3:
> > - Added to the set
> >
> > Cc: Daniel Vetter <daniel@xxxxxxxx>
> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> > Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> > Cc: Ben Skeggs <bskeggs@xxxxxxxxxx>
> > Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > Cc: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
> > Cc: Eric Anholt <eric@xxxxxxxxxx>
> > Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
> > ---
> > 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

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Next message: Sean Paul: "Re: [PATCH 3/5] dt-bindings: msm/disp: Introduce interconnect bindings for MDSS on SDM845"
Previous message: Oded Gabbay: "[PATCH] habanalabs: increase PCI ELBI timeout for Palladium"
In reply to: Sean Paul: "Re: [PATCH v3 04/10] drm: Convert connector_helper_funcs->atomic_check to accept drm_atomic_state"
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