Re: [PATCH v3 6/6] drm/ingenic: Attach bridge chain to encoders

From: Laurent Pinchart
Date: Thu Sep 23 2021 - 05:23:11 EST

Next message: Oded Gabbay: "Re: [PATCH v6 0/2] Add p2p via dmabuf to habanalabs"
Previous message: Mike Galbraith: "Re: [PATCH 2/2] sched/fair: Scale wakeup granularity relative to nr_running"
In reply to: Paul Boddie: "Re: [PATCH v3 6/6] drm/ingenic: Attach bridge chain to encoders"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hello,

On Thu, Sep 23, 2021 at 09:49:03AM +0100, Paul Cercueil wrote:
> Le jeu., sept. 23 2021 at 07:52:08 +0200, H. Nikolaus Schaller a écrit :
> > Hi Paul,
> > thanks for another update.
> >
> > We have been delayed to rework the CI20 HDMI code on top of your series
> > but it basically works in some situations. There is for example a problem
> > if the EDID reports DRM_COLOR_FORMAT_YCRCB422 but it appears to be outside
> > of your series.
>
> I think the SoC can output YCbCr as well, but I never tried to use it.
>
> > The only issue we have is described below.
> >
> >> Am 22.09.2021 um 22:55 schrieb Paul Cercueil <paul@xxxxxxxxxxxxxxx>:
> >>
> >> Attach a top-level bridge to each encoder, which will be used for
> >> negociating the bus format and flags.
> >>
> >> All the bridges are now attached with DRM_BRIDGE_ATTACH_NO_CONNECTOR.
> >>
> >> Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >> ---
> >> drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 92 +++++++++++++++++------
> >> 1 file changed, 70 insertions(+), 22 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >> index a5e2880e07a1..a05a9fa6e115 100644
> >> --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >> +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >> @@ -21,6 +21,7 @@
> >> #include <drm/drm_atomic.h>
> >> #include <drm/drm_atomic_helper.h>
> >> #include <drm/drm_bridge.h>
> >> +#include <drm/drm_bridge_connector.h>
> >> #include <drm/drm_color_mgmt.h>
> >> #include <drm/drm_crtc.h>
> >> #include <drm/drm_crtc_helper.h>
> >> @@ -108,6 +109,19 @@ struct ingenic_drm {
> >> struct drm_private_obj private_obj;
> >> };
> >>
> >> +struct ingenic_drm_bridge {
> >> + struct drm_encoder encoder;
> >> + struct drm_bridge bridge, *next_bridge;
> >> +
> >> + struct drm_bus_cfg bus_cfg;
> >> +};
> >> +
> >> +static inline struct ingenic_drm_bridge *
> >> +to_ingenic_drm_bridge(struct drm_encoder *encoder)
> >> +{
> >> + return container_of(encoder, struct ingenic_drm_bridge, encoder);
> >> +}
> >> +
> >> static inline struct ingenic_drm_private_state *
> >> to_ingenic_drm_priv_state(struct drm_private_state *state)
> >> {
> >> @@ -668,11 +682,10 @@ static void ingenic_drm_encoder_atomic_mode_set(struct drm_encoder *encoder,
> >> {
> >> struct ingenic_drm *priv = drm_device_get_priv(encoder->dev);
> >> struct drm_display_mode *mode = &crtc_state->adjusted_mode;
> >> - struct drm_connector *conn = conn_state->connector;
> >> - struct drm_display_info *info = &conn->display_info;
> >> + struct ingenic_drm_bridge *bridge = to_ingenic_drm_bridge(encoder);
> >> unsigned int cfg, rgbcfg = 0;
> >>
> >> - priv->panel_is_sharp = info->bus_flags & DRM_BUS_FLAG_SHARP_SIGNALS;
> >> + priv->panel_is_sharp = bridge->bus_cfg.flags & DRM_BUS_FLAG_SHARP_SIGNALS;
> >>
> >> if (priv->panel_is_sharp) {
> >> cfg = JZ_LCD_CFG_MODE_SPECIAL_TFT_1 | JZ_LCD_CFG_REV_POLARITY;
> >> @@ -685,19 +698,19 @@ static void ingenic_drm_encoder_atomic_mode_set(struct drm_encoder *encoder,
> >> cfg |= JZ_LCD_CFG_HSYNC_ACTIVE_LOW;
> >> if (mode->flags & DRM_MODE_FLAG_NVSYNC)
> >> cfg |= JZ_LCD_CFG_VSYNC_ACTIVE_LOW;
> >> - if (info->bus_flags & DRM_BUS_FLAG_DE_LOW)
> >> + if (bridge->bus_cfg.flags & DRM_BUS_FLAG_DE_LOW)
> >> cfg |= JZ_LCD_CFG_DE_ACTIVE_LOW;
> >> - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
> >> + if (bridge->bus_cfg.flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
> >> cfg |= JZ_LCD_CFG_PCLK_FALLING_EDGE;
> >>
> >> if (!priv->panel_is_sharp) {
> >> - if (conn->connector_type == DRM_MODE_CONNECTOR_TV) {
> >> + if (conn_state->connector->connector_type == DRM_MODE_CONNECTOR_TV) {
> >> if (mode->flags & DRM_MODE_FLAG_INTERLACE)
> >> cfg |= JZ_LCD_CFG_MODE_TV_OUT_I;
> >> else
> >> cfg |= JZ_LCD_CFG_MODE_TV_OUT_P;
> >> } else {
> >> - switch (*info->bus_formats) {
> >> + switch (bridge->bus_cfg.format) {
> >> case MEDIA_BUS_FMT_RGB565_1X16:
> >> cfg |= JZ_LCD_CFG_MODE_GENERIC_16BIT;
> >> break;
> >> @@ -723,20 +736,29 @@ static void ingenic_drm_encoder_atomic_mode_set(struct drm_encoder *encoder,
> >> regmap_write(priv->map, JZ_REG_LCD_RGBC, rgbcfg);
> >> }
> >>
> >> -static int ingenic_drm_encoder_atomic_check(struct drm_encoder *encoder,
> >> - struct drm_crtc_state *crtc_state,
> >> - struct drm_connector_state *conn_state)
> >> +static int ingenic_drm_bridge_attach(struct drm_bridge *bridge,
> >> + enum drm_bridge_attach_flags flags)
> >> +{
> >> + struct ingenic_drm_bridge *ib = to_ingenic_drm_bridge(bridge->encoder);
> >> +
> >> + return drm_bridge_attach(bridge->encoder, ib->next_bridge,
> >> + &ib->bridge, flags);
> >> +}
> >> +
> >> +static int ingenic_drm_bridge_atomic_check(struct drm_bridge *bridge,
> >> + struct drm_bridge_state *bridge_state,
> >> + struct drm_crtc_state *crtc_state,
> >> + struct drm_connector_state *conn_state)
> >> {
> >> - struct drm_display_info *info = &conn_state->connector->display_info;
> >> struct drm_display_mode *mode = &crtc_state->adjusted_mode;
> >> + struct ingenic_drm_bridge *ib = to_ingenic_drm_bridge(bridge->encoder);
> >>
> >> - if (info->num_bus_formats != 1)
> >> - return -EINVAL;
> >> + ib->bus_cfg = bridge_state->output_bus_cfg;
> >>
> >> if (conn_state->connector->connector_type == DRM_MODE_CONNECTOR_TV)
> >> return 0;
> >>
> >> - switch (*info->bus_formats) {
> >> + switch (bridge_state->output_bus_cfg.format) {
> >> case MEDIA_BUS_FMT_RGB888_3X8:
> >> case MEDIA_BUS_FMT_RGB888_3X8_DELTA:
> >> /*
> >> @@ -900,8 +922,16 @@ static const struct drm_crtc_helper_funcs ingenic_drm_crtc_helper_funcs = {
> >> };
> >>
> >> static const struct drm_encoder_helper_funcs ingenic_drm_encoder_helper_funcs = {
> >> - .atomic_mode_set = ingenic_drm_encoder_atomic_mode_set,
> >> - .atomic_check = ingenic_drm_encoder_atomic_check,
> >> + .atomic_mode_set = ingenic_drm_encoder_atomic_mode_set,
> >> +};
> >> +
> >> +static const struct drm_bridge_funcs ingenic_drm_bridge_funcs = {
> >> + .attach = ingenic_drm_bridge_attach,
> >> + .atomic_check = ingenic_drm_bridge_atomic_check,
> >> + .atomic_reset = drm_atomic_helper_bridge_reset,
> >> + .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> >> + .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> >> + .atomic_get_input_bus_fmts = drm_atomic_helper_bridge_propagate_bus_fmt,
> >> };
> >>
> >> static const struct drm_mode_config_funcs ingenic_drm_mode_config_funcs = {
> >> @@ -976,7 +1006,9 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
> >> struct drm_plane *primary;
> >> struct drm_bridge *bridge;
> >> struct drm_panel *panel;
> >> + struct drm_connector *connector;
> >> struct drm_encoder *encoder;
> >> + struct ingenic_drm_bridge *ib;
> >> struct drm_device *drm;
> >> void __iomem *base;
> >> long parent_rate;
> >> @@ -1154,20 +1186,36 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
> >> bridge = devm_drm_panel_bridge_add_typed(dev, panel,
> >> DRM_MODE_CONNECTOR_DPI);
> >>
> >> - encoder = drmm_plain_encoder_alloc(drm, NULL, DRM_MODE_ENCODER_DPI, NULL);
> >> - if (IS_ERR(encoder)) {
> >> - ret = PTR_ERR(encoder);
> >> + ib = drmm_encoder_alloc(drm, struct ingenic_drm_bridge, encoder,
> >> + NULL, DRM_MODE_ENCODER_DPI, NULL);
> >> + if (IS_ERR(ib)) {
> >> + ret = PTR_ERR(ib);
> >> dev_err(dev, "Failed to init encoder: %d\n", ret);
> >> return ret;
> >> }
> >>
> >> - encoder->possible_crtcs = 1;
> >> + encoder = &ib->encoder;
> >> + encoder->possible_crtcs = drm_crtc_mask(&priv->crtc);
> >>
> >> drm_encoder_helper_add(encoder, &ingenic_drm_encoder_helper_funcs);
> >>
> >> - ret = drm_bridge_attach(encoder, bridge, NULL, 0);
> >> - if (ret)
> >> + ib->bridge.funcs = &ingenic_drm_bridge_funcs;
> >> + ib->next_bridge = bridge;
> >> +
> >> + ret = drm_bridge_attach(encoder, &ib->bridge, NULL,
> >> + DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> >
> > DRM_BRIDGE_ATTACH_NO_CONNECTOR makes it fundamentally incompatible
> > with synopsys/dw_hdmi.c
> >
> > That driver checks for DRM_BRIDGE_ATTACH_NO_CONNECTOR being NOT present,
> > since it wants to register its own connector through
> > dw_hdmi_connector_create().

Does it ? The driver has

static int dw_hdmi_bridge_attach(struct drm_bridge *bridge,
enum drm_bridge_attach_flags flags)
{
struct dw_hdmi *hdmi = bridge->driver_private;

if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
return drm_bridge_attach(bridge->encoder, hdmi->next_bridge,
bridge, flags);

return dw_hdmi_connector_create(hdmi);
}

If DRM_BRIDGE_ATTACH_NO_CONNECTOR is not set, it will create a
connector, otherwise it will just attach to the next bridge. I'm using
it on a Renesas platform with the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag
set, without any issue as far as I can tell.

> > It does it for a reason: the dw-hdmi is a multi-function driver which does
> > HDMI and DDC/EDID stuff in a single driver (because I/O registers and power
> > management seem to be shared).
>
> The IT66121 driver does all of that too, and does not need
> DRM_BRIDGE_ATTACH_NO_CONNECTOR. The drm_bridge_funcs struct has
> callbacks to handle cable detection and DDC stuff.
>
> > Since I do not see who could split this into a separate bridge and a connector driver
> > and test it on multiple SoC platforms (there are at least 3 or 4), I think modifying
> > the fundamentals of the dw-hdmi architecture just to get CI20 HDMI working is not
> > our turf.
>
> You could have a field in the dw-hdmi pdata structure, that would
> instruct the driver whether or not it should use the new API. Ugly, I
> know, and would probably duplicate a lot of code, but that would allow
> other drivers to be updated at a later date.
>
> > Therefore the code here should be able to detect if drm_bridge_attach() already
> > creates and attaches a connector and then skip the code below.
>
> Not that easy, unfortunately. On one side we have dw-hdmi which checks
> that DRM_BRIDGE_ATTACH_NO_CONNECTOR is not set, and on the other side
> we have other drivers like the IT66121 which will fail if this flag is
> not set.

> >> + if (ret) {
> >> + dev_err(dev, "Unable to attach bridge\n");
> >> return ret;
> >> + }
> >> +
> >> + connector = drm_bridge_connector_init(drm, encoder);
> >> + if (IS_ERR(connector)) {
> >> + dev_err(dev, "Unable to init connector\n");
> >> + return PTR_ERR(connector);
> >> + }
> >> +
> >> + drm_connector_attach_encoder(connector, encoder);
> >> }
> >>
> >> drm_for_each_encoder(encoder, drm) {
> >> --
> >> 2.33.0
> >
> > I haven't replaced v2 with v3 in our test tree yet, but will do asap.

--
Regards,

Laurent Pinchart

Next message: Oded Gabbay: "Re: [PATCH v6 0/2] Add p2p via dmabuf to habanalabs"
Previous message: Mike Galbraith: "Re: [PATCH 2/2] sched/fair: Scale wakeup granularity relative to nr_running"
In reply to: Paul Boddie: "Re: [PATCH v3 6/6] drm/ingenic: Attach bridge chain to encoders"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]