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Date: Wed, 26 Jun 2024 14:28:57 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Aradhya Bhatia <a-bhatia1@...com>,
Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Jyri Sarha <jyri.sarha@....fi>,
Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
Daniel Vetter <daniel@...ll.ch>
Cc: DRI Development List <dri-devel@...ts.freedesktop.org>,
Linux Kernel List <linux-kernel@...r.kernel.org>,
Dominik Haller <d.haller@...tec.de>, Sam Ravnborg <sam@...nborg.org>,
Thierry Reding <treding@...dia.com>,
Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
Nishanth Menon <nm@...com>, Vignesh Raghavendra <vigneshr@...com>,
Praneeth Bajjuri <praneeth@...com>, Udit Kumar <u-kumar1@...com>,
Devarsh Thakkar <devarsht@...com>, Jayesh Choudhary <j-choudhary@...com>,
Jai Luthra <j-luthra@...com>
Subject: Re: [PATCH v4 10/11] drm/atomic-helper: Re-order bridge chain
pre-enable and post-disable
On 22/06/2024 14:09, Aradhya Bhatia wrote:
> Move the bridge pre_enable call before crtc enable, and the bridge
> post_disable call after the crtc disable.
>
> The sequence of enable after this patch will look like:
>
> bridge[n]_pre_enable
> ...
> bridge[1]_pre_enable
>
> crtc_enable
> encoder_enable
>
> bridge[1]_enable
> ...
> bridge[n]__enable
>
> and vice-versa for the bridge chain disable sequence.
>
> The definition of bridge pre_enable hook says that,
> "The display pipe (i.e. clocks and timing signals) feeding this bridge
> will not yet be running when this callback is called".
>
> Since CRTC is also a source feeding the bridge, it should not be enabled
> before the bridges in the pipeline are pre_enabled. Fix that by
> re-ordering the sequence of bridge pre_enable and bridge post_disable.
>
> Signed-off-by: Aradhya Bhatia <a-bhatia1@...com>
> ---
> drivers/gpu/drm/drm_atomic_helper.c | 165 ++++++++++++++++++----------
> include/drm/drm_atomic_helper.h | 7 ++
> 2 files changed, 114 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index fb97b51b38f1..e8ad08634f58 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -74,6 +74,7 @@
> * also shares the &struct drm_plane_helper_funcs function table with the plane
> * helpers.
> */
> +
Extra change.
> static void
> drm_atomic_helper_plane_changed(struct drm_atomic_state *state,
> struct drm_plane_state *old_plane_state,
> @@ -1122,11 +1123,11 @@ crtc_needs_disable(struct drm_crtc_state *old_state,
> }
>
> static void
> -disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> +disable_encoder_brige_chain(struct drm_device *dev, struct drm_atomic_state *old_state,
> + enum bridge_chain_operation_type op_type)
> {
> struct drm_connector *connector;
> struct drm_connector_state *old_conn_state, *new_conn_state;
> - struct drm_crtc *crtc;
> struct drm_crtc_state *old_crtc_state, *new_crtc_state;
> int i;
>
> @@ -1163,32 +1164,55 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> if (WARN_ON(!encoder))
> continue;
>
> - funcs = encoder->helper_private;
> -
> - drm_dbg_atomic(dev, "disabling [ENCODER:%d:%s]\n",
> - encoder->base.id, encoder->name);
> -
> /*
> * Each encoder has at most one connector (since we always steal
> * it away), so we won't call disable hooks twice.
> */
> bridge = drm_bridge_chain_get_first_bridge(encoder);
> - drm_atomic_bridge_chain_disable(bridge, old_state);
>
> - /* Right function depends upon target state. */
> - if (funcs) {
> - if (funcs->atomic_disable)
> - funcs->atomic_disable(encoder, old_state);
> - else if (new_conn_state->crtc && funcs->prepare)
> - funcs->prepare(encoder);
> - else if (funcs->disable)
> - funcs->disable(encoder);
> - else if (funcs->dpms)
> - funcs->dpms(encoder, DRM_MODE_DPMS_OFF);
> - }
> + switch (op_type) {
> + case DRM_ENCODER_BRIDGE_DISABLE:
> + funcs = encoder->helper_private;
> +
> + drm_dbg_atomic(dev, "disabling [ENCODER:%d:%s]\n",
> + encoder->base.id, encoder->name);
> +
> + drm_atomic_bridge_chain_disable(bridge, old_state);
> +
> + /* Right function depends upon target state. */
> + if (funcs) {
> + if (funcs->atomic_disable)
> + funcs->atomic_disable(encoder, old_state);
> + else if (new_conn_state->crtc && funcs->prepare)
> + funcs->prepare(encoder);
> + else if (funcs->disable)
> + funcs->disable(encoder);
> + else if (funcs->dpms)
> + funcs->dpms(encoder, DRM_MODE_DPMS_OFF);
> + }
> +
> + break;
> +
> + case DRM_BRIDGE_POST_DISABLE:
> + drm_atomic_bridge_chain_post_disable(bridge, old_state);
>
> - drm_atomic_bridge_chain_post_disable(bridge, old_state);
> + break;
> +
> + default:
> + drm_err(dev, "Unrecognized Encoder/Bridge Operation (%d).\n", op_type);
> + break;
> + }
> }
> +}
> +
> +static void
> +disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> +{
> + struct drm_crtc *crtc;
> + struct drm_crtc_state *old_crtc_state, *new_crtc_state;
> + int i;
> +
> + disable_encoder_brige_chain(dev, old_state, DRM_ENCODER_BRIDGE_DISABLE);
>
> for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
> const struct drm_crtc_helper_funcs *funcs;
> @@ -1234,6 +1258,8 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> if (ret == 0)
> drm_crtc_vblank_put(crtc);
> }
> +
> + disable_encoder_brige_chain(dev, old_state, DRM_BRIDGE_POST_DISABLE);
> }
>
> /**
> @@ -1445,6 +1471,64 @@ static void drm_atomic_helper_commit_writebacks(struct drm_device *dev,
> }
> }
>
> +static void
> +enable_encoder_brige_chain(struct drm_device *dev, struct drm_atomic_state *old_state,
> + enum bridge_chain_operation_type op_type)
> +{
> + struct drm_connector *connector;
> + struct drm_connector_state *new_conn_state;
> + int i;
> +
> + for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
> + const struct drm_encoder_helper_funcs *funcs;
> + struct drm_encoder *encoder;
> + struct drm_bridge *bridge;
> +
> + if (!new_conn_state->best_encoder)
> + continue;
> +
> + if (!new_conn_state->crtc->state->active ||
> + !drm_atomic_crtc_needs_modeset(new_conn_state->crtc->state))
> + continue;
> +
> + encoder = new_conn_state->best_encoder;
> +
> + /*
> + * Each encoder has at most one connector (since we always steal
> + * it away), so we won't call enable hooks twice.
> + */
> + bridge = drm_bridge_chain_get_first_bridge(encoder);
> +
> + switch (op_type) {
> + case DRM_BRIDGE_PRE_ENABLE:
> + drm_atomic_bridge_chain_pre_enable(bridge, old_state);
> + break;
> +
> + case DRM_ENCODER_BRIDGE_ENABLE:
> + funcs = encoder->helper_private;
> +
> + drm_dbg_atomic(dev, "enabling [ENCODER:%d:%s]\n",
> + encoder->base.id, encoder->name);
> +
> + if (funcs) {
> + if (funcs->atomic_enable)
> + funcs->atomic_enable(encoder, old_state);
> + else if (funcs->enable)
> + funcs->enable(encoder);
> + else if (funcs->commit)
> + funcs->commit(encoder);
> + }
> +
> + drm_atomic_bridge_chain_enable(bridge, old_state);
> + break;
> +
> + default:
> + drm_err(dev, "Unrecognized Encoder/Bridge Operation (%d).\n", op_type);
> + break;
> + }
> + }
> +}
> +
> /**
> * drm_atomic_helper_commit_modeset_enables - modeset commit to enable outputs
> * @dev: DRM device
> @@ -1465,10 +1549,10 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
> struct drm_crtc *crtc;
> struct drm_crtc_state *old_crtc_state;
> struct drm_crtc_state *new_crtc_state;
> - struct drm_connector *connector;
> - struct drm_connector_state *new_conn_state;
> int i;
>
> + enable_encoder_brige_chain(dev, old_state, DRM_BRIDGE_PRE_ENABLE);
> +
> for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
> const struct drm_crtc_helper_funcs *funcs;
>
> @@ -1491,42 +1575,7 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
> }
> }
>
> - for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
> - const struct drm_encoder_helper_funcs *funcs;
> - struct drm_encoder *encoder;
> - struct drm_bridge *bridge;
> -
> - if (!new_conn_state->best_encoder)
> - continue;
> -
> - if (!new_conn_state->crtc->state->active ||
> - !drm_atomic_crtc_needs_modeset(new_conn_state->crtc->state))
> - continue;
> -
> - encoder = new_conn_state->best_encoder;
> - funcs = encoder->helper_private;
> -
> - drm_dbg_atomic(dev, "enabling [ENCODER:%d:%s]\n",
> - encoder->base.id, encoder->name);
> -
> - /*
> - * Each encoder has at most one connector (since we always steal
> - * it away), so we won't call enable hooks twice.
> - */
> - bridge = drm_bridge_chain_get_first_bridge(encoder);
> - drm_atomic_bridge_chain_pre_enable(bridge, old_state);
> -
> - if (funcs) {
> - if (funcs->atomic_enable)
> - funcs->atomic_enable(encoder, old_state);
> - else if (funcs->enable)
> - funcs->enable(encoder);
> - else if (funcs->commit)
> - funcs->commit(encoder);
> - }
> -
> - drm_atomic_bridge_chain_enable(bridge, old_state);
> - }
> + enable_encoder_brige_chain(dev, old_state, DRM_ENCODER_BRIDGE_ENABLE);
>
> drm_atomic_helper_commit_writebacks(dev, old_state);
> }
> diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> index 9aa0a05aa072..b45a175a9f8a 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -43,6 +43,13 @@
> */
> #define DRM_PLANE_NO_SCALING (1<<16)
>
> +enum bridge_chain_operation_type {
> + DRM_BRIDGE_PRE_ENABLE,
> + DRM_BRIDGE_POST_DISABLE,
> + DRM_ENCODER_BRIDGE_ENABLE,
> + DRM_ENCODER_BRIDGE_DISABLE,
> +};
Why are the last two "DRM_ENCODER"?
I don't like the enum... Having "enum bridge_chain_operation_type" as a
parameter to a function looks like one can pass any of the enum's
values, which is not the case.
How about an enum with just two values:
DRM_BRIDGE_PRE_ENABLE_POST_DISABLE
DRM_BRIDGE_ENABLE_DISABLE
Tomi
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