Re: [Freedreno] [PATCH v2 4/4] drm/msm/dsi: switch to DRM_PANEL_BRIDGE

[Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>]

On 7/12/2022 1:10 PM, Dmitry Baryshkov wrote:
> On Tue, 12 Jul 2022 at 22:15, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
> > On 7/12/2022 3:00 AM, Dmitry Baryshkov wrote:
> > > On Tue, 12 Jul 2022 at 01:39, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
> > > > On 7/11/2022 2:43 AM, Dmitry Baryshkov wrote:
> > > > > Currently the DSI driver has two separate paths: one if the next device
> > > > > in a chain is a bridge and another one if the panel is connected
> > > > > directly to the DSI host. Simplify the code path by using panel-bridge
> > > > > driver (already selected in Kconfig) and dropping support for
> > > > > handling the panel directly.
> > > > >
> > > > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > > > > ---
> > > > >     drivers/gpu/drm/msm/dsi/dsi.c         |  38 +---
> > > > >     drivers/gpu/drm/msm/dsi/dsi.h         |  14 +-
> > > > >     drivers/gpu/drm/msm/dsi/dsi_host.c    |  25 ---
> > > > >     drivers/gpu/drm/msm/dsi/dsi_manager.c | 264 ++------------------------
> > > > >     4 files changed, 26 insertions(+), 315 deletions(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
> > > > > index 1625328fa430..3c53e28092db 100644
> > > > > --- a/drivers/gpu/drm/msm/dsi/dsi.c
> > > > > +++ b/drivers/gpu/drm/msm/dsi/dsi.c
> > > > > @@ -6,14 +6,6 @@
> > > > >     #include "dsi.h"
> > > > >     #include "dsi_cfg.h"
> > > > >
> > > > > -struct drm_encoder *msm_dsi_get_encoder(struct msm_dsi *msm_dsi)
> > > > > -{
> > > > > -     if (!msm_dsi || !msm_dsi_device_connected(msm_dsi))
> > > > > -             return NULL;
> > > > > -
> > > > > -     return msm_dsi->encoder;
> > > > > -}
> > > >
> > > > panel_bridge doesnt have the best_encoder method today.
> > > > Today, this does not break anything for us.
> > > > But, for future if we do need it, panel_bridge needs to be expanded to
> > > > add that method?
> > >
> > > We have a 1:1 between encoder and connector, so
> > > drm_connector_get_single_encoder() works well in our case.
> > like I said before, today this should be fine.
> > If we do come up with a use-case in future to have the best_encoder()
> > panel_bridge will need to be expanded. So this is more of a comment to
> > keep in mind but no change needed for this.
>
> Do you think we can end up with a DSI encoder being handled by
> multiple connectors?

No, i dont foresee such a case.

Even if we enable ping-pong split in the future that will still have 
only one connector.

> > > > > -
> > > > >     bool msm_dsi_is_cmd_mode(struct msm_dsi *msm_dsi)
> > > > >     {
> > > > >         unsigned long host_flags = msm_dsi_host_get_mode_flags(msm_dsi->host);
> > > > > @@ -220,7 +212,7 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
> > > > >                          struct drm_encoder *encoder)
> > > > >     {
> > > > >         struct msm_drm_private *priv;
> > > > > -     struct drm_bridge *ext_bridge;
> > > > > +     struct drm_connector *connector;
> > > > >         int ret;
> > > > >
> > > > >         if (WARN_ON(!encoder) || WARN_ON(!msm_dsi) || WARN_ON(!dev))
> > > > > @@ -254,26 +246,12 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
> > > > >                 goto fail;
> > > > >         }
> > > > >
> > > > > -     /*
> > > > > -      * check if the dsi encoder output is connected to a panel or an
> > > > > -      * external bridge. We create a connector only if we're connected to a
> > > > > -      * drm_panel device. When we're connected to an external bridge, we
> > > > > -      * assume that the drm_bridge driver will create the connector itself.
> > > > > -      */
> > > > > -     ext_bridge = msm_dsi_host_get_bridge(msm_dsi->host);
> > > > > -
> > > > > -     if (ext_bridge)
> > > > > -             msm_dsi->connector =
> > > > > -                     msm_dsi_manager_ext_bridge_init(msm_dsi->id);
> > > > > -     else
> > > > > -             msm_dsi->connector =
> > > > > -                     msm_dsi_manager_connector_init(msm_dsi->id);
> > > > > -
> > > > > -     if (IS_ERR(msm_dsi->connector)) {
> > > > > -             ret = PTR_ERR(msm_dsi->connector);
> > > > > +     connector = msm_dsi_manager_ext_bridge_init(msm_dsi->id);
> > > > > +
> > > > > +     if (IS_ERR(connector)) {
> > > > > +             ret = PTR_ERR(connector);
> > > > >                 DRM_DEV_ERROR(dev->dev,
> > > > >                         "failed to create dsi connector: %d\n", ret);
> > > > > -             msm_dsi->connector = NULL;
> > > > >                 goto fail;
> > > > >         }
> > > > >
> > > > > @@ -287,12 +265,6 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
> > > > >                 msm_dsi->bridge = NULL;
> > > > >         }
> > > > >
> > > > > -     /* don't destroy connector if we didn't make it */
> > > > > -     if (msm_dsi->connector && !msm_dsi->external_bridge)
> > > > > -             msm_dsi->connector->funcs->destroy(msm_dsi->connector);
> > > > > -
> > > > > -     msm_dsi->connector = NULL;
> > > > > -
> > > > >         return ret;
> > > > >     }
> > > > >
> > > > > diff --git a/drivers/gpu/drm/msm/dsi/dsi.h b/drivers/gpu/drm/msm/dsi/dsi.h
> > > > > index 580a1e6358bf..41630b8f5358 100644
> > > > > --- a/drivers/gpu/drm/msm/dsi/dsi.h
> > > > > +++ b/drivers/gpu/drm/msm/dsi/dsi.h
> > > > > @@ -12,7 +12,6 @@
> > > > >     #include <drm/drm_bridge.h>
> > > > >     #include <drm/drm_crtc.h>
> > > > >     #include <drm/drm_mipi_dsi.h>
> > > > > -#include <drm/drm_panel.h>
> > > > >
> > > > >     #include "msm_drv.h"
> > > > >     #include "disp/msm_disp_snapshot.h"
> > > > > @@ -49,8 +48,6 @@ struct msm_dsi {
> > > > >         struct drm_device *dev;
> > > > >         struct platform_device *pdev;
> > > > >
> > > > > -     /* connector managed by us when we're connected to a drm_panel */
> > > > > -     struct drm_connector *connector;
> > > > >         /* internal dsi bridge attached to MDP interface */
> > > > >         struct drm_bridge *bridge;
> > > > >
> > > > > @@ -58,10 +55,8 @@ struct msm_dsi {
> > > > >         struct msm_dsi_phy *phy;
> > > > >
> > > > >         /*
> > > > > -      * panel/external_bridge connected to dsi bridge output, only one of the
> > > > > -      * two can be valid at a time
> > > > > +      * external_bridge connected to dsi bridge output
> > > > >          */
> > > > > -     struct drm_panel *panel;
> > > > >         struct drm_bridge *external_bridge;
> > > > >
> > > > >         struct device *phy_dev;
> > > > > @@ -76,7 +71,6 @@ struct msm_dsi {
> > > > >     /* dsi manager */
> > > > >     struct drm_bridge *msm_dsi_manager_bridge_init(u8 id);
> > > > >     void msm_dsi_manager_bridge_destroy(struct drm_bridge *bridge);
> > > > > -struct drm_connector *msm_dsi_manager_connector_init(u8 id);
> > > > >     struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id);
> > > > >     int msm_dsi_manager_cmd_xfer(int id, const struct mipi_dsi_msg *msg);
> > > > >     bool msm_dsi_manager_cmd_xfer_trigger(int id, u32 dma_base, u32 len);
> > > > > @@ -87,11 +81,9 @@ void msm_dsi_manager_tpg_enable(void);
> > > > >     /* msm dsi */
> > > > >     static inline bool msm_dsi_device_connected(struct msm_dsi *msm_dsi)
> > > > >     {
> > > > > -     return msm_dsi->panel || msm_dsi->external_bridge;
> > > > > +     return msm_dsi->external_bridge;
> > > > >     }
> > > > >
> > > > > -struct drm_encoder *msm_dsi_get_encoder(struct msm_dsi *msm_dsi);
> > > > > -
> > > > >     /* dsi host */
> > > > >     struct msm_dsi_host;
> > > > >     int msm_dsi_host_xfer_prepare(struct mipi_dsi_host *host,
> > > > > @@ -116,9 +108,7 @@ int msm_dsi_host_set_display_mode(struct mipi_dsi_host *host,
> > > > >                                   const struct drm_display_mode *mode);
> > > > >     enum drm_mode_status msm_dsi_host_check_dsc(struct mipi_dsi_host *host,
> > > > >                                             const struct drm_display_mode *mode);
> > > > > -struct drm_panel *msm_dsi_host_get_panel(struct mipi_dsi_host *host);
> > > > >     unsigned long msm_dsi_host_get_mode_flags(struct mipi_dsi_host *host);
> > > > > -struct drm_bridge *msm_dsi_host_get_bridge(struct mipi_dsi_host *host);
> > > > >     int msm_dsi_host_register(struct mipi_dsi_host *host);
> > > > >     void msm_dsi_host_unregister(struct mipi_dsi_host *host);
> > > > >     void msm_dsi_host_set_phy_mode(struct mipi_dsi_host *host,
> > > > > diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > > > > index fb5ab6c718c8..5a18aa710d00 100644
> > > > > --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> > > > > +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > > > > @@ -164,7 +164,6 @@ struct msm_dsi_host {
> > > > >         struct msm_display_dsc_config *dsc;
> > > > >
> > > > >         /* connected device info */
> > > > > -     struct device_node *device_node;
> > > > >         unsigned int channel;
> > > > >         unsigned int lanes;
> > > > >         enum mipi_dsi_pixel_format format;
> > > > > @@ -1721,8 +1720,6 @@ static int dsi_host_detach(struct mipi_dsi_host *host,
> > > > >
> > > > >         dsi_dev_detach(msm_host->pdev);
> > > > >
> > > > > -     msm_host->device_node = NULL;
> > > > > -
> > > > >         DBG("id=%d", msm_host->id);
> > > > >         if (msm_host->dev)
> > > > >                 queue_work(msm_host->workqueue, &msm_host->hpd_work);
> > > > > @@ -1988,16 +1985,6 @@ static int dsi_host_parse_dt(struct msm_dsi_host *msm_host)
> > > > >                 goto err;
> > > > >         }
> > > > >
> > > > > -     /* Get panel node from the output port's endpoint data */
> > > > > -     device_node = of_graph_get_remote_node(np, 1, 0);
> > > > > -     if (!device_node) {
> > > > > -             DRM_DEV_DEBUG(dev, "%s: no valid device\n", __func__);
> > > > > -             ret = -ENODEV;
> > > > > -             goto err;
> > > > > -     }
> > > > > -
> > > > > -     msm_host->device_node = device_node;
> > > > > -
> > > > >         if (of_property_read_bool(np, "syscon-sfpb")) {
> > > > >                 msm_host->sfpb = syscon_regmap_lookup_by_phandle(np,
> > > > >                                         "syscon-sfpb");
> > > > > @@ -2678,23 +2665,11 @@ enum drm_mode_status msm_dsi_host_check_dsc(struct mipi_dsi_host *host,
> > > > >         return MODE_OK;
> > > > >     }
> > > > >
> > > > > -struct drm_panel *msm_dsi_host_get_panel(struct mipi_dsi_host *host)
> > > > > -{
> > > > > -     return of_drm_find_panel(to_msm_dsi_host(host)->device_node);
> > > > > -}
> > > > > -
> > > > >     unsigned long msm_dsi_host_get_mode_flags(struct mipi_dsi_host *host)
> > > > >     {
> > > > >         return to_msm_dsi_host(host)->mode_flags;
> > > > >     }
> > > > >
> > > > > -struct drm_bridge *msm_dsi_host_get_bridge(struct mipi_dsi_host *host)
> > > > > -{
> > > > > -     struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
> > > > > -
> > > > > -     return of_drm_find_bridge(msm_host->device_node);
> > > > > -}
> > > > > -
> > > > >     void msm_dsi_host_snapshot(struct msm_disp_state *disp_state, struct mipi_dsi_host *host)
> > > > >     {
> > > > >         struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
> > > > > diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
> > > > > index cb84d185d73a..3970368e07d5 100644
> > > > > --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
> > > > > +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
> > > > > @@ -214,39 +214,26 @@ static void dsi_mgr_phy_disable(int id)
> > > > >         }
> > > > >     }
> > > > >
> > > > > -struct dsi_connector {
> > > > > -     struct drm_connector base;
> > > > > -     int id;
> > > > > -};
> > > > > -
> > > > >     struct dsi_bridge {
> > > > >         struct drm_bridge base;
> > > > >         int id;
> > > > >     };
> > > > >
> > > > > -#define to_dsi_connector(x) container_of(x, struct dsi_connector, base)
> > > > >     #define to_dsi_bridge(x) container_of(x, struct dsi_bridge, base)
> > > > >
> > > > > -static inline int dsi_mgr_connector_get_id(struct drm_connector *connector)
> > > > > -{
> > > > > -     struct dsi_connector *dsi_connector = to_dsi_connector(connector);
> > > > > -     return dsi_connector->id;
> > > > > -}
> > > > > -
> > > > >     static int dsi_mgr_bridge_get_id(struct drm_bridge *bridge)
> > > > >     {
> > > > >         struct dsi_bridge *dsi_bridge = to_dsi_bridge(bridge);
> > > > >         return dsi_bridge->id;
> > > > >     }
> > > > >
> > > > > -static int msm_dsi_manager_panel_init(struct drm_connector *conn, u8 id)
> > > > > +static void msm_dsi_manager_set_split_display(u8 id)
> > > > >     {
> > > > > -     struct msm_drm_private *priv = conn->dev->dev_private;
> > > > > -     struct msm_kms *kms = priv->kms;
> > > > >         struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > >         struct msm_dsi *other_dsi = dsi_mgr_get_other_dsi(id);
> > > > > +     struct msm_drm_private *priv = msm_dsi->dev->dev_private;
> > > > > +     struct msm_kms *kms = priv->kms;
> > > > >         struct msm_dsi *master_dsi, *slave_dsi;
> > > > > -     struct drm_panel *panel;
> > > > >
> > > > >         if (IS_BONDED_DSI() && !IS_MASTER_DSI_LINK(id)) {
> > > > >                 master_dsi = other_dsi;
> > > > > @@ -256,89 +243,18 @@ static int msm_dsi_manager_panel_init(struct drm_connector *conn, u8 id)
> > > > >                 slave_dsi = other_dsi;
> > > > >         }
> > > > >
> > > > > -     /*
> > > > > -      * There is only 1 panel in the global panel list for bonded DSI mode.
> > > > > -      * Therefore slave dsi should get the drm_panel instance from master
> > > > > -      * dsi.
> > > > > -      */
> > > > > -     panel = msm_dsi_host_get_panel(master_dsi->host);
> > > > > -     if (IS_ERR(panel)) {
> > > > > -             DRM_ERROR("Could not find panel for %u (%ld)\n", msm_dsi->id,
> > > > > -                       PTR_ERR(panel));
> > > > > -             return PTR_ERR(panel);
> > > > > -     }
> > > > > -
> > > > > -     if (!panel || !IS_BONDED_DSI())
> > > > > -             goto out;
> > > > > -
> > > > > -     drm_object_attach_property(&conn->base,
> > > > > -                                conn->dev->mode_config.tile_property, 0);
> > > > > +     if (!msm_dsi->external_bridge || !IS_BONDED_DSI())
> > > > > +             return;
> > > > >
> > > > >         /*
> > > > >          * Set split display info to kms once bonded DSI panel is connected to
> > > > >          * both hosts.
> > > > >          */
> > > > > -     if (other_dsi && other_dsi->panel && kms->funcs->set_split_display) {
> > > > > +     if (other_dsi && other_dsi->external_bridge && kms->funcs->set_split_display) {
> > > > >                 kms->funcs->set_split_display(kms, master_dsi->encoder,
> > > > >                                               slave_dsi->encoder,
> > > > >                                               msm_dsi_is_cmd_mode(msm_dsi));
> > > > >         }
> > > > > -
> > > > > -out:
> > > > > -     msm_dsi->panel = panel;
> > > > > -     return 0;
> > > > > -}
> > > > > -
> > > > > -static enum drm_connector_status dsi_mgr_connector_detect(
> > > > > -             struct drm_connector *connector, bool force)
> > > > > -{
> > > > > -     int id = dsi_mgr_connector_get_id(connector);
> > > > > -     struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > > -
> > > > > -     return msm_dsi->panel ? connector_status_connected :
> > > > > -             connector_status_disconnected;
> > > > > -}
> > > > > -
> > > > > -static void dsi_mgr_connector_destroy(struct drm_connector *connector)
> > > > > -{
> > > > > -     struct dsi_connector *dsi_connector = to_dsi_connector(connector);
> > > > > -
> > > > > -     DBG("");
> > > > > -
> > > > > -     drm_connector_cleanup(connector);
> > > > > -
> > > > > -     kfree(dsi_connector);
> > > > > -}
> > > > > -
> > > > > -static int dsi_mgr_connector_get_modes(struct drm_connector *connector)
> > > > > -{
> > > > > -     int id = dsi_mgr_connector_get_id(connector);
> > > > > -     struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > > -     struct drm_panel *panel = msm_dsi->panel;
> > > > > -     int num;
> > > > > -
> > > > > -     if (!panel)
> > > > > -             return 0;
> > > > > -
> > > > > -     /*
> > > > > -      * In bonded DSI mode, we have one connector that can be
> > > > > -      * attached to the drm_panel.
> > > > > -      */
> > > > > -     num = drm_panel_get_modes(panel, connector);
> > > > > -     if (!num)
> > > > > -             return 0;
> > > > > -
> > > > > -     return num;
> > > > > -}
> > > > > -
> > > > > -static struct drm_encoder *
> > > > > -dsi_mgr_connector_best_encoder(struct drm_connector *connector)
> > > > > -{
> > > > > -     int id = dsi_mgr_connector_get_id(connector);
> > > > > -     struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > > -
> > > > > -     DBG("");
> > > > > -     return msm_dsi_get_encoder(msm_dsi);
> > > > >     }
> > > > >
> > > > >     static void dsi_mgr_bridge_power_on(struct drm_bridge *bridge)
> > > > > @@ -403,7 +319,6 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
> > > > >         struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > >         struct msm_dsi *msm_dsi1 = dsi_mgr_get_dsi(DSI_1);
> > > > >         struct mipi_dsi_host *host = msm_dsi->host;
> > > > > -     struct drm_panel *panel = msm_dsi->panel;
> > > > >         bool is_bonded_dsi = IS_BONDED_DSI();
> > > > >         int ret;
> > > > >
> > > > > @@ -418,18 +333,6 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
> > > > >         if (!dsi_mgr_power_on_early(bridge))
> > > > >                 dsi_mgr_bridge_power_on(bridge);
> > > > >
> > > > > -     /* Always call panel functions once, because even for dual panels,
> > > > > -      * there is only one drm_panel instance.
> > > > > -      */
> > > > > -     if (panel) {
> > > > > -             ret = drm_panel_prepare(panel);
> > > > > -             if (ret) {
> > > > > -                     pr_err("%s: prepare panel %d failed, %d\n", __func__,
> > > > > -                                                             id, ret);
> > > > > -                     goto panel_prep_fail;
> > > > > -             }
> > > > > -     }
> > > > > -
> > > > >         ret = msm_dsi_host_enable(host);
> > > > >         if (ret) {
> > > > >                 pr_err("%s: enable host %d failed, %d\n", __func__, id, ret);
> > > > > @@ -449,9 +352,6 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
> > > > >     host1_en_fail:
> > > > >         msm_dsi_host_disable(host);
> > > > >     host_en_fail:
> > > > > -     if (panel)
> > > > > -             drm_panel_unprepare(panel);
> > > > > -panel_prep_fail:
> > > > >
> > > > >         return;
> > > > >     }
> > > > > @@ -469,62 +369,12 @@ void msm_dsi_manager_tpg_enable(void)
> > > > >         }
> > > > >     }
> > > > >
> > > > > -static void dsi_mgr_bridge_enable(struct drm_bridge *bridge)
> > > > > -{
> > > > > -     int id = dsi_mgr_bridge_get_id(bridge);
> > > > > -     struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > > -     struct drm_panel *panel = msm_dsi->panel;
> > > > > -     bool is_bonded_dsi = IS_BONDED_DSI();
> > > > > -     int ret;
> > > > > -
> > > > > -     DBG("id=%d", id);
> > > > > -     if (!msm_dsi_device_connected(msm_dsi))
> > > > > -             return;
> > > > > -
> > > > > -     /* Do nothing with the host if it is slave-DSI in case of bonded DSI */
> > > > > -     if (is_bonded_dsi && !IS_MASTER_DSI_LINK(id))
> > > > > -             return;
> > > > > -
> > > > > -     if (panel) {
> > > > > -             ret = drm_panel_enable(panel);
> > > > > -             if (ret) {
> > > > > -                     pr_err("%s: enable panel %d failed, %d\n", __func__, id,
> > > > > -                                                                     ret);
> > > > > -             }
> > > > > -     }
> > > > > -}
> > > > > -
> > > > > -static void dsi_mgr_bridge_disable(struct drm_bridge *bridge)
> > > > > -{
> > > > > -     int id = dsi_mgr_bridge_get_id(bridge);
> > > > > -     struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > > -     struct drm_panel *panel = msm_dsi->panel;
> > > > > -     bool is_bonded_dsi = IS_BONDED_DSI();
> > > > > -     int ret;
> > > > > -
> > > > > -     DBG("id=%d", id);
> > > > > -     if (!msm_dsi_device_connected(msm_dsi))
> > > > > -             return;
> > > > > -
> > > > > -     /* Do nothing with the host if it is slave-DSI in case of bonded DSI */
> > > > > -     if (is_bonded_dsi && !IS_MASTER_DSI_LINK(id))
> > > > > -             return;
> > > > > -
> > > > > -     if (panel) {
> > > > > -             ret = drm_panel_disable(panel);
> > > > > -             if (ret)
> > > > > -                     pr_err("%s: Panel %d OFF failed, %d\n", __func__, id,
> > > > > -                                                                     ret);
> > > > > -     }
> > > > > -}
> > > > > -
> > > > >     static void dsi_mgr_bridge_post_disable(struct drm_bridge *bridge)
> > > > >     {
> > > > >         int id = dsi_mgr_bridge_get_id(bridge);
> > > > >         struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > >         struct msm_dsi *msm_dsi1 = dsi_mgr_get_dsi(DSI_1);
> > > > >         struct mipi_dsi_host *host = msm_dsi->host;
> > > > > -     struct drm_panel *panel = msm_dsi->panel;
> > > > >         bool is_bonded_dsi = IS_BONDED_DSI();
> > > > >         int ret;
> > > > >
> > > > > @@ -551,13 +401,6 @@ static void dsi_mgr_bridge_post_disable(struct drm_bridge *bridge)
> > > > >                         pr_err("%s: host1 disable failed, %d\n", __func__, ret);
> > > > >         }
> > > > >
> > > > > -     if (panel) {
> > > > > -             ret = drm_panel_unprepare(panel);
> > > > > -             if (ret)
> > > > > -                     pr_err("%s: Panel %d unprepare failed,%d\n", __func__,
> > > > > -                                                             id, ret);
> > > > > -     }
> > > > > -
> > > > >         msm_dsi_host_disable_irq(host);
> > > > >         if (is_bonded_dsi && msm_dsi1)
> > > > >                 msm_dsi_host_disable_irq(msm_dsi1->host);
> > > > > @@ -614,76 +457,13 @@ static enum drm_mode_status dsi_mgr_bridge_mode_valid(struct drm_bridge *bridge,
> > > > >         return msm_dsi_host_check_dsc(host, mode);
> > > > >     }
> > > > >
> > > > > -static const struct drm_connector_funcs dsi_mgr_connector_funcs = {
> > > > > -     .detect = dsi_mgr_connector_detect,
> > > > > -     .fill_modes = drm_helper_probe_single_connector_modes,
> > > > > -     .destroy = dsi_mgr_connector_destroy,
> > > > > -     .reset = drm_atomic_helper_connector_reset,
> > > > > -     .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> > > > > -     .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> > > > > -};
> > > > > -
> > > > > -static const struct drm_connector_helper_funcs dsi_mgr_conn_helper_funcs = {
> > > > > -     .get_modes = dsi_mgr_connector_get_modes,
> > > > > -     .best_encoder = dsi_mgr_connector_best_encoder,
> > > > > -};
> > > > > -
> > > > >     static const struct drm_bridge_funcs dsi_mgr_bridge_funcs = {
> > > > >         .pre_enable = dsi_mgr_bridge_pre_enable,
> > > > > -     .enable = dsi_mgr_bridge_enable,
> > > > > -     .disable = dsi_mgr_bridge_disable,
> > > > >         .post_disable = dsi_mgr_bridge_post_disable,
> > > > >         .mode_set = dsi_mgr_bridge_mode_set,
> > > > >         .mode_valid = dsi_mgr_bridge_mode_valid,
> > > > >     };
> > > > >
> > > > > -/* initialize connector when we're connected to a drm_panel */
> > > > > -struct drm_connector *msm_dsi_manager_connector_init(u8 id)
> > > > > -{
> > > > > -     struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> > > > > -     struct drm_connector *connector = NULL;
> > > > > -     struct dsi_connector *dsi_connector;
> > > > > -     int ret;
> > > > > -
> > > > > -     dsi_connector = kzalloc(sizeof(*dsi_connector), GFP_KERNEL);
> > > > > -     if (!dsi_connector)
> > > > > -             return ERR_PTR(-ENOMEM);
> > > > > -
> > > > > -     dsi_connector->id = id;
> > > > > -
> > > > > -     connector = &dsi_connector->base;
> > > > > -
> > > > > -     ret = drm_connector_init(msm_dsi->dev, connector,
> > > > > -                     &dsi_mgr_connector_funcs, DRM_MODE_CONNECTOR_DSI);
> > > > > -     if (ret)
> > > > > -             return ERR_PTR(ret);
> > > > > -
> > > > > -     drm_connector_helper_add(connector, &dsi_mgr_conn_helper_funcs);
> > > > > -
> > > > > -     /* Enable HPD to let hpd event is handled
> > > > > -      * when panel is attached to the host.
> > > > > -      */
> > > > > -     connector->polled = DRM_CONNECTOR_POLL_HPD;
> > > >
> > > > I see that this part gets removed with this migration.
> > > >
> > > > For fixed/built-in displays, it should not matter i think but i am not
> > > > sure if some usermodes might expect this even for DSI?
> > > >
> > > > So, once again does panel_bridge needs to account for this?
> > >
> > > Panel bridge sets only DRM_BRIDGE_OP_MODES. If you check the existing
> > > code, the dsi_mgr_connector also does not provide HPD support. It only
> > > can return panel status depending on whether the drm_panel was fetched
> > > or not. No events are generated ever.
> > > Thus said I think we should stop hijacking the usual mechanisms. If we
> > > do not do the HPD, let's not declare it. If there is a case of panel
> > > being hotplugged or switched, it will be handled by the next bridge in
> > > the chain, not by the MSM DSI code.
> > hot plug events are sent today.
> >
> >
> > static void dsi_hpd_worker(struct work_struct *work)
> > {
> >       struct msm_dsi_host *msm_host =
> >           container_of(work, struct msm_dsi_host, hpd_work);
> >
> >       drm_helper_hpd_irq_event(msm_host->dev);
> > }
> >
> > If you are planning to drop DRM_CONNECTOR_POLL_HPD, then you should
> > remove all this code as well because its just dead code otherwise.
>
> This is scheduled at dsi_host_attach() / dsi_host_detach(), so it's
> not a dead code.

What I mean by dead code is that if you do not set 
DRM_CONNECTOR_POLL_HPD, then no hotplug event is sent today.

https://gitlab.freedesktop.org/drm/msm/-/blob/msm-next/drivers/gpu/drm/drm_probe_helper.c#L941

And if we are not sending hotplug event, why keep this wq and call
drm_helper_hpd_irq_event()?

> We can probably inline the dsi_hpd_worker, but it's a separate change.

> > I agree, the hot plug handling can be done by the next bridge in the chain.
> >
> > Then lets cleanup this code too.
> >
> > > > > -
> > > > > -     /* Display driver doesn't support interlace now. */
> > > > > -     connector->interlace_allowed = 0;
> > > > > -     connector->doublescan_allowed = 0;
> > > > > -
> > > > > -     drm_connector_attach_encoder(connector, msm_dsi->encoder);
> > > > > -
> > > > > -     ret = msm_dsi_manager_panel_init(connector, id);
> > > > > -     if (ret) {
> > > > > -             DRM_DEV_ERROR(msm_dsi->dev->dev, "init panel failed %d\n", ret);
> > > > > -             goto fail;
> > > > > -     }
> > > > > -
> > > > > -     return connector;
> > > > > -
> > > > > -fail:
> > > > > -     connector->funcs->destroy(connector);
> > > > > -     return ERR_PTR(ret);
> > > > > -}
> > > > > -
> > > > >     /* initialize bridge */
> > > > >     struct drm_bridge *msm_dsi_manager_bridge_init(u8 id)
> > > > >     {
> > > > > @@ -732,8 +512,11 @@ struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id)
> > > > >         int ret;
> > > > >
> > > > >         int_bridge = msm_dsi->bridge;
> > > > > -     ext_bridge = msm_dsi->external_bridge =
> > > > > -                     msm_dsi_host_get_bridge(msm_dsi->host);
> > > > > +     ext_bridge = devm_drm_of_get_bridge(&msm_dsi->pdev->dev, msm_dsi->pdev->dev.of_node, 1, 0);
> > > > > +     if (IS_ERR(ext_bridge))
> > > > > +             return ERR_CAST(ext_bridge);
> > > > > +
> > > > > +     msm_dsi->external_bridge = ext_bridge;
> > > > >
> > > > >         encoder = msm_dsi->encoder;
> > > > >
> > > > > @@ -745,25 +528,12 @@ struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id)
> > > > >         ret = drm_bridge_attach(encoder, ext_bridge, int_bridge,
> > > > >                         DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> > > > >         if (ret == -EINVAL) {
> > > > > -             struct drm_connector *connector;
> > > > > -             struct list_head *connector_list;
> > > > > -
> > > > >                 /* link the internal dsi bridge to the external bridge */
> > > > > -             drm_bridge_attach(encoder, ext_bridge, int_bridge, 0);
> > > > > +             ret = drm_bridge_attach(encoder, ext_bridge, int_bridge, 0);
> > > > > +             if (ret < 0)
> > > > > +                     return ERR_PTR(ret);
> > > > >
> > > > > -             /*
> > > > > -              * we need the drm_connector created by the external bridge
> > > > > -              * driver (or someone else) to feed it to our driver's
> > > > > -              * priv->connector[] list, mainly for msm_fbdev_init()
> > > > > -              */
> > > > > -             connector_list = &dev->mode_config.connector_list;
> > > > > -
> > > > > -             list_for_each_entry(connector, connector_list, head) {
> > > > > -                     if (drm_connector_has_possible_encoder(connector, encoder))
> > > > > -                             return connector;
> > > > > -             }
> > > > > -
> > > > > -             return ERR_PTR(-ENODEV);
> > > > > +             goto out;
> > > > >         }
> > > > >
> > > > >         connector = drm_bridge_connector_init(dev, encoder);
> > > > > @@ -774,6 +544,10 @@ struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id)
> > > > >
> > > > >         drm_connector_attach_encoder(connector, encoder);
> > > > >
> > > > > +out:
> > > > > +     /* The pipeline is ready, ping encoders if necessary */
> > > > > +     msm_dsi_manager_set_split_display(id);
> > > > Do you still want to execute msm_dsi_manager_set_split_display even for
> > > > the error case? Like in the above lines you have replaced the return
> > > > ERR_PTR() with the goto out. But do you want to then move the
> > > > set_split_display() call above the out label?
> > >
> > > You see, the return ERR_PTR was the error case, where we could not
> > > find the connector corresponding to the encoder.
> > > We just don't need it anymore. Let's change the function to return int
> > > rather than the unused connector.
> > >
> > > > Also, now for the cases where there was an error where the connector was
> > > > not found, we will return a NULL ptr instead of the ERR_PTR(-ENODEV).
> > > > Is that expected?
> > >
> > > Yes. We just do not care anymore about this connector.
> >
> > My question was do you want to skip even
> > msm_dsi_manager_set_split_display(id) by moving it above the out label.
>
> No. The 'out' was a path around creating our own DSI connector. I've
> refactored this piece of code in v2.5. Maybe it would be more obvious
> now.

Ok, let me review v2.5 for this part.

>