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Message-ID: <vso7eistcemnv7hyk6nj27imqtckpqwglkpuidpzt4cfyluklj@42lci2ecv7sk>
Date: Sun, 20 Oct 2024 14:58:18 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Aradhya Bhatia <aradhya.bhatia@...ux.dev>
Cc: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>, Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, Jonas Karlman <jonas@...boo.se>,
Jernej Skrabec <jernej.skrabec@...il.com>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Dominik Haller <d.haller@...tec.de>, Sam Ravnborg <sam@...nborg.org>,
Kieran Bingham <kieran.bingham+renesas@...asonboard.com>, Nishanth Menon <nm@...com>,
Vignesh Raghavendra <vigneshr@...com>, Devarsh Thakkar <devarsht@...com>,
Praneeth Bajjuri <praneeth@...com>, Udit Kumar <u-kumar1@...com>,
Jayesh Choudhary <j-choudhary@...com>, DRI Development List <dri-devel@...ts.freedesktop.org>,
Linux Kernel List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 12/13] drm/atomic-helper: Re-order bridge chain
pre-enable and post-disable
On Sun, Oct 20, 2024 at 01:35:29AM +0530, Aradhya Bhatia wrote:
> From: Aradhya Bhatia <a-bhatia1@...com>
>
> 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>
> Signed-off-by: Aradhya Bhatia <aradhya.bhatia@...ux.dev>
> ---
> drivers/gpu/drm/drm_atomic_helper.c | 102 ++++++++++++++++++----------
> include/drm/drm_atomic_helper.h | 5 ++
> 2 files changed, 71 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 7741fbcc8fc7..6ebd869df79b 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1122,7 +1122,8 @@ crtc_needs_disable(struct drm_crtc_state *old_state,
> }
>
> static void
> -encoder_bridge_chain_disable(struct drm_device *dev, struct drm_atomic_state *old_state)
> +encoder_bridge_chain_disable(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;
> @@ -1162,31 +1163,43 @@ encoder_bridge_chain_disable(struct drm_device *dev, struct drm_atomic_state *ol
> 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_BRIDGE_ENABLE_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);
> + }
>
> - drm_atomic_bridge_chain_post_disable(bridge, old_state);
> + break;
> +
> + case DRM_BRIDGE_PRE_ENABLE_POST_DISABLE:
> + drm_atomic_bridge_chain_post_disable(bridge, old_state);
> + break;
> +
> + default:
> + drm_err(dev, "Unrecognized Encoder/Bridge Operation (%d).\n", op_type);
> + break;
> + }
> }
> }
>
> @@ -1197,7 +1210,7 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> struct drm_crtc_state *old_crtc_state, *new_crtc_state;
> int i;
>
> - encoder_bridge_chain_disable(dev, old_state);
> + encoder_bridge_chain_disable(dev, old_state, DRM_BRIDGE_ENABLE_DISABLE);
>
> for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
> const struct drm_crtc_helper_funcs *funcs;
> @@ -1243,6 +1256,8 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> if (ret == 0)
> drm_crtc_vblank_put(crtc);
> }
> +
> + encoder_bridge_chain_disable(dev, old_state, DRM_BRIDGE_PRE_ENABLE_POST_DISABLE);
> }
>
> /**
> @@ -1455,7 +1470,8 @@ static void drm_atomic_helper_commit_writebacks(struct drm_device *dev,
> }
>
> static void
> -encoder_bridge_chain_enable(struct drm_device *dev, struct drm_atomic_state *old_state)
> +encoder_bridge_chain_enable(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;
> @@ -1474,28 +1490,40 @@ encoder_bridge_chain_enable(struct drm_device *dev, struct drm_atomic_state *old
> 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);
> - }
> + switch (op_type) {
> + case DRM_BRIDGE_PRE_ENABLE_POST_DISABLE:
> + drm_atomic_bridge_chain_pre_enable(bridge, old_state);
> + break;
> +
> + case DRM_BRIDGE_ENABLE_DISABLE:
> + funcs = encoder->helper_private;
> +
> + drm_dbg_atomic(dev, "enabling [ENCODER:%d:%s]\n",
> + encoder->base.id, encoder->name);
>
> - drm_atomic_bridge_chain_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);
> + break;
> +
> + default:
> + drm_err(dev, "Unrecognized Encoder/Bridge Operation (%d).\n", op_type);
> + break;
> + }
> }
> }
>
> @@ -1521,6 +1549,8 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
> struct drm_crtc_state *new_crtc_state;
> int i;
>
> + encoder_bridge_chain_enable(dev, old_state, DRM_BRIDGE_PRE_ENABLE_POST_DISABLE);
> +
> for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
> const struct drm_crtc_helper_funcs *funcs;
>
> @@ -1543,7 +1573,7 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
> }
> }
>
> - encoder_bridge_chain_enable(dev, old_state);
> + encoder_bridge_chain_enable(dev, old_state, DRM_BRIDGE_ENABLE_DISABLE);
>
> 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..92a5812adc6c 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -43,6 +43,11 @@
> */
> #define DRM_PLANE_NO_SCALING (1<<16)
>
> +enum bridge_chain_operation_type {
> + DRM_BRIDGE_PRE_ENABLE_POST_DISABLE,
> + DRM_BRIDGE_ENABLE_DISABLE,
> +};
> +
The enum doesn't need to be public, does it?
> struct drm_atomic_state;
> struct drm_private_obj;
> struct drm_private_state;
> --
> 2.34.1
>
--
With best wishes
Dmitry
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