4.13.2. connector代码分析
4.13.2.1. drm_connector结构体
struct drm_connector {
/** @dev: parent DRM device */
struct drm_device *dev;
/** @kdev: kernel device for sysfs attributes */
struct device *kdev;
/** @attr: sysfs attributes */
struct device_attribute *attr;
/**
* @head:
*
* List of all connectors on a @dev, linked from
* &drm_mode_config.connector_list. Protected by
* &drm_mode_config.connector_list_lock, but please only use
* &drm_connector_list_iter to walk this list.
*/
struct list_head head;
/** @base: base KMS object */
struct drm_mode_object base;
/** @name: human readable name, can be overwritten by the driver */
char *name;
/**
* @mutex: Lock for general connector state, but currently only protects
* @registered. Most of the connector state is still protected by
* &drm_mode_config.mutex.
*/
struct mutex mutex;
/**
* @index: Compacted connector index, which matches the position inside
* the mode_config.list for drivers not supporting hot-add/removing. Can
* be used as an array index. It is invariant over the lifetime of the
* connector.
*/
unsigned index;
/**
* @connector_type:
* one of the DRM_MODE_CONNECTOR_<foo> types from drm_mode.h
*/
int connector_type;
/** @connector_type_id: index into connector type enum */
int connector_type_id;
/**
* @interlace_allowed:
* Can this connector handle interlaced modes? Only used by
* drm_helper_probe_single_connector_modes() for mode filtering.
*/
bool interlace_allowed;
/**
* @doublescan_allowed:
* Can this connector handle doublescan? Only used by
* drm_helper_probe_single_connector_modes() for mode filtering.
*/
bool doublescan_allowed;
/**
* @stereo_allowed:
* Can this connector handle stereo modes? Only used by
* drm_helper_probe_single_connector_modes() for mode filtering.
*/
bool stereo_allowed;
/**
* @ycbcr_420_allowed : This bool indicates if this connector is
* capable of handling YCBCR 420 output. While parsing the EDID
* blocks it's very helpful to know if the source is capable of
* handling YCBCR 420 outputs.
*/
bool ycbcr_420_allowed;
/**
* @registration_state: Is this connector initializing, exposed
* (registered) with userspace, or unregistered?
*
* Protected by @mutex.
*/
enum drm_connector_registration_state registration_state;
/**
* @modes:
* Modes available on this connector (from fill_modes() + user).
* Protected by &drm_mode_config.mutex.
*/
struct list_head modes;
/**
* @status:
* One of the drm_connector_status enums (connected, not, or unknown).
* Protected by &drm_mode_config.mutex.
*/
enum drm_connector_status status;
/**
* @probed_modes:
* These are modes added by probing with DDC or the BIOS, before
* filtering is applied. Used by the probe helpers. Protected by
* &drm_mode_config.mutex.
*/
struct list_head probed_modes;
/**
* @display_info: Display information is filled from EDID information
* when a display is detected. For non hot-pluggable displays such as
* flat panels in embedded systems, the driver should initialize the
* &drm_display_info.width_mm and &drm_display_info.height_mm fields
* with the physical size of the display.
*
* Protected by &drm_mode_config.mutex.
*/
struct drm_display_info display_info;
/** @funcs: connector control functions */
const struct drm_connector_funcs *funcs;
/**
* @edid_blob_ptr: DRM property containing EDID if present. Protected by
* &drm_mode_config.mutex. This should be updated only by calling
* drm_connector_update_edid_property().
*/
struct drm_property_blob *edid_blob_ptr;
/** @properties: property tracking for this connector */
struct drm_object_properties properties;
/**
* @scaling_mode_property: Optional atomic property to control the
* upscaling. See drm_connector_attach_content_protection_property().
*/
struct drm_property *scaling_mode_property;
/**
* @vrr_capable_property: Optional property to help userspace
* query hardware support for variable refresh rate on a connector.
* connector. Drivers can add the property to a connector by
* calling drm_connector_attach_vrr_capable_property().
*
* This should be updated only by calling
* drm_connector_set_vrr_capable_property().
*/
struct drm_property *vrr_capable_property;
/**
* @colorspace_property: Connector property to set the suitable
* colorspace supported by the sink.
*/
struct drm_property *colorspace_property;
/**
* @path_blob_ptr:
*
* DRM blob property data for the DP MST path property. This should only
* be updated by calling drm_connector_set_path_property().
*/
struct drm_property_blob *path_blob_ptr;
/**
* @max_bpc_property: Default connector property for the max bpc to be
* driven out of the connector.
*/
struct drm_property *max_bpc_property;
#define DRM_CONNECTOR_POLL_HPD (1 << 0)
#define DRM_CONNECTOR_POLL_CONNECT (1 << 1)
#define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2)
/**
* @polled:
*
* Connector polling mode, a combination of
*
* DRM_CONNECTOR_POLL_HPD
* The connector generates hotplug events and doesn't need to be
* periodically polled. The CONNECT and DISCONNECT flags must not
* be set together with the HPD flag.
*
* DRM_CONNECTOR_POLL_CONNECT
* Periodically poll the connector for connection.
*
* DRM_CONNECTOR_POLL_DISCONNECT
* Periodically poll the connector for disconnection, without
* causing flickering even when the connector is in use. DACs should
* rarely do this without a lot of testing.
*
* Set to 0 for connectors that don't support connection status
* discovery.
*/
uint8_t polled;
/**
* @dpms: Current dpms state. For legacy drivers the
* &drm_connector_funcs.dpms callback must update this. For atomic
* drivers, this is handled by the core atomic code, and drivers must
* only take &drm_crtc_state.active into account.
*/
int dpms;
/** @helper_private: mid-layer private data */
const struct drm_connector_helper_funcs *helper_private;
/** @cmdline_mode: mode line parsed from the kernel cmdline for this connector */
struct drm_cmdline_mode cmdline_mode;
/** @force: a DRM_FORCE_<foo> state for forced mode sets */
enum drm_connector_force force;
/** @override_edid: has the EDID been overwritten through debugfs for testing? */
bool override_edid;
#define DRM_CONNECTOR_MAX_ENCODER 3
/**
* @encoder_ids: Valid encoders for this connector. Please only use
* drm_connector_for_each_possible_encoder() to enumerate these.
*/
uint32_t encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
/**
* @encoder: Currently bound encoder driving this connector, if any.
* Only really meaningful for non-atomic drivers. Atomic drivers should
* instead look at &drm_connector_state.best_encoder, and in case they
* need the CRTC driving this output, &drm_connector_state.crtc.
*/
struct drm_encoder *encoder;
#define MAX_ELD_BYTES 128
/** @eld: EDID-like data, if present */
uint8_t eld[MAX_ELD_BYTES];
/** @latency_present: AV delay info from ELD, if found */
bool latency_present[2];
/**
* @video_latency: Video latency info from ELD, if found.
* [0]: progressive, [1]: interlaced
*/
int video_latency[2];
/**
* @audio_latency: audio latency info from ELD, if found
* [0]: progressive, [1]: interlaced
*/
int audio_latency[2];
/**
* @ddc: associated ddc adapter.
* A connector usually has its associated ddc adapter. If a driver uses
* this field, then an appropriate symbolic link is created in connector
* sysfs directory to make it easy for the user to tell which i2c
* adapter is for a particular display.
*
* The field should be set by calling drm_connector_init_with_ddc().
*/
struct i2c_adapter *ddc;
/**
* @null_edid_counter: track sinks that give us all zeros for the EDID.
* Needed to workaround some HW bugs where we get all 0s
*/
int null_edid_counter;
/** @bad_edid_counter: track sinks that give us an EDID with invalid checksum */
unsigned bad_edid_counter;
/**
* @edid_corrupt: Indicates whether the last read EDID was corrupt. Used
* in Displayport compliance testing - Displayport Link CTS Core 1.2
* rev1.1 4.2.2.6
*/
bool edid_corrupt;
/** @debugfs_entry: debugfs directory for this connector */
struct dentry *debugfs_entry;
/**
* @state:
*
* Current atomic state for this connector.
*
* This is protected by &drm_mode_config.connection_mutex. Note that
* nonblocking atomic commits access the current connector state without
* taking locks. Either by going through the &struct drm_atomic_state
* pointers, see for_each_oldnew_connector_in_state(),
* for_each_old_connector_in_state() and
* for_each_new_connector_in_state(). Or through careful ordering of
* atomic commit operations as implemented in the atomic helpers, see
* &struct drm_crtc_commit.
*/
struct drm_connector_state *state;
/* DisplayID bits. FIXME: Extract into a substruct? */
/**
* @tile_blob_ptr:
*
* DRM blob property data for the tile property (used mostly by DP MST).
* This is meant for screens which are driven through separate display
* pipelines represented by &drm_crtc, which might not be running with
* genlocked clocks. For tiled panels which are genlocked, like
* dual-link LVDS or dual-link DSI, the driver should try to not expose
* the tiling and virtualize both &drm_crtc and &drm_plane if needed.
*
* This should only be updated by calling
* drm_connector_set_tile_property().
*/
struct drm_property_blob *tile_blob_ptr;
/** @has_tile: is this connector connected to a tiled monitor */
bool has_tile;
/** @tile_group: tile group for the connected monitor */
struct drm_tile_group *tile_group;
/** @tile_is_single_monitor: whether the tile is one monitor housing */
bool tile_is_single_monitor;
/** @num_h_tile: number of horizontal tiles in the tile group */
/** @num_v_tile: number of vertical tiles in the tile group */
uint8_t num_h_tile, num_v_tile;
/** @tile_h_loc: horizontal location of this tile */
/** @tile_v_loc: vertical location of this tile */
uint8_t tile_h_loc, tile_v_loc;
/** @tile_h_size: horizontal size of this tile. */
/** @tile_v_size: vertical size of this tile. */
uint16_t tile_h_size, tile_v_size;
/**
* @free_node:
*
* List used only by &drm_connector_list_iter to be able to clean up a
* connector from any context, in conjunction with
* &drm_mode_config.connector_free_work.
*/
struct llist_node free_node;
/** @hdr_sink_metadata: HDR Metadata Information read from sink */
struct hdr_sink_metadata hdr_sink_metadata;
};
drm_connector的主要初始化接口为 drm_connector_init
drm_connector_init
int drm_connector_init(struct drm_device *dev,
struct drm_connector *connector,
const struct drm_connector_funcs *funcs,
int connector_type)
{
//获取drm_mode_config结构体，一个drm设备只有一个struct drm_mode_config结构体
//里面配置了一些参数
struct drm_mode_config *config = &dev->mode_config;
int ret;
//获取connector_ida，后面会分配
struct ida *connector_ida =
&drm_connector_enum_list[connector_type].ida;
WARN_ON(drm_drv_uses_atomic_modeset(dev) &&
(!funcs->atomic_destroy_state ||
!funcs->atomic_duplicate_state));
//生成类型为DRM_MODE_OBJECT_CONNECTOR的struct drm_mode_object结构体
//connector->base.id会在用户态接口drmModeGetResources调用时，作为connector_id返回用户态
//后续用户态可以通过connector_id，调用drmModeGetConnector找到drm_connector，并获取相关参数
ret = __drm_mode_object_add(dev, &connector->base,
DRM_MODE_OBJECT_CONNECTOR,
false, drm_connector_free);
if (ret)
return ret;
//得到properties
connector->base.properties = &connector->properties;
connector->dev = dev;
connector->funcs = funcs;
//生成drm_mode_config的connector_ida并作为该connector的index索引
/* connector index is used with 32bit bitmasks */
ret = ida_simple_get(&config->connector_ida, 0, 32, GFP_KERNEL);
if (ret < 0) {
DRM_DEBUG_KMS("Failed to allocate %s connector index: %d\n",
drm_connector_enum_list[connector_type].name,
ret);
goto out_put;
}
connector->index = ret;
ret = 0;
//生成该connector的type的connector_ida
connector->connector_type = connector_type;
connector->connector_type_id =
ida_simple_get(connector_ida, 1, 0, GFP_KERNEL);
if (connector->connector_type_id < 0) {
ret = connector->connector_type_id;
goto out_put_id;
}
//初始化connector名称及链表，mutex等
connector->name =
kasprintf(GFP_KERNEL, "%s-%d",
drm_connector_enum_list[connector_type].name,
connector->connector_type_id);
if (!connector->name) {
ret = -ENOMEM;
goto out_put_type_id;
}
INIT_LIST_HEAD(&connector->probed_modes);
INIT_LIST_HEAD(&connector->modes);
mutex_init(&connector->mutex);
connector->edid_blob_ptr = NULL;
connector->tile_blob_ptr = NULL;
connector->status = connector_status_unknown;
connector->display_info.panel_orientation =
DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
drm_connector_get_cmdline_mode(connector);
/* We should add connectors at the end to avoid upsetting the connector
* index too much. */
spin_lock_irq(&config->connector_list_lock);
list_add_tail(&connector->head, &config->connector_list);
config->num_connector++;
spin_unlock_irq(&config->connector_list_lock);
if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL &&
connector_type != DRM_MODE_CONNECTOR_WRITEBACK)
drm_connector_attach_edid_property(connector);
drm_object_attach_property(&connector->base,
config->dpms_property, 0);
drm_object_attach_property(&connector->base,
config->link_status_property,
0);
drm_object_attach_property(&connector->base,
config->non_desktop_property,
0);
drm_object_attach_property(&connector->base,
config->tile_property,
0);
if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
drm_object_attach_property(&connector->base, config->prop_crtc_id, 0);
}
connector->debugfs_entry = NULL;
out_put_type_id:
if (ret)
ida_simple_remove(connector_ida, connector->connector_type_id);
out_put_id:
if (ret)
ida_simple_remove(&config->connector_ida, connector->index);
out_put:
if (ret)
drm_mode_object_unregister(dev, &connector->base);
return ret;
}
4.13.2.2. 用户态操作
用户态获取connector_id逻辑
//用户态
drmModeGetResources
drmIoctl(fd, DRM_IOCTL_MODE_GETRESOURCES, &res)
//res.crtc_id_ptr指向设备的所有crtc_id
//内核态
DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, 0)
drm_mode_getresources
drm_connector_list_iter_begin(dev, &conn_iter)
drm_for_each_connector_iter(connector, &conn_iter) //遍历connector
put_user(connector->base.id, connector_id + count) //拷贝id到用户态
drm_connector_list_iter_end(&conn_iter)
用户态根据connector_id获取drm_connector
//用户态
drmModeGetConnector()
conn.connector_id = connector_id
drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, &conn)
//内核态
DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCONNECTOR, drm_mode_getconnector, 0)
drm_mode_getconnector
connector = drm_connector_lookup(dev, file_priv, out_resp->connector_id)
//根据用户态传进来的id和type
mo = drm_mode_object_find(dev, file_priv, id, DRM_MODE_OBJECT_CONNECTOR)
return obj_to_connector(mo)
base.properties
记录connector的属性(如CRTC_ID/EDID/等),这些属性首先在drm_mode_create_standard_properties创建初始化并保存在 dev->mode_config中
//以CRTC_ID属性为例
drm_mode_config_init
drmm_mode_config_init
drm_mode_create_standard_properties
//创建名称为DRTC_ID的属性
prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC, "CRTC_ID", DRM_MDOE_OBJECT_CRTC)
//创建属性
drm_property_create
//将该property保存在mode_config的property_list链表
list_add_tail(&property->head, &dev->mode_config.property_list)
//保存到mode_config.prop_crtc_id中
dev->mode_config.prop_crtc_id = prop
properties的获取
//用户态
drmModeObjectGetProperties
//通过connector_id以及DRM_MODE_OBJECT_CONNECTOR获取其属性
drmIoctl(fd, DRM_IOCTL_MODE_OBJ_GETPROPERTIES, &properties)
//内核态
DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_GETPROPERTIES, drm_mode_obj_get_properties_ioctl, 0)
//根据obj_id(connector_id)和obj_type(DRM_MODE_OBJECT_CONNECTOR)获取connector的drm_mode_object实例obj
obj = drm_mode_object_find(dev, file_priv, arg->obj_id, arg->obj_type)
//遍历connector->base.properties并拷贝到用户态
//这里仅拷贝了properties的id和value，并没有拷贝名称
drm_mode_object_get_properties(obj, file_priv->atomic, arg->props_ptr, arg->prop_values_ptr, ...)
//上述获取的是connector的所有属性id, value, 如果要获取特定名称的属性，还需如下操作
//用户态
drmModeGetProperty
drmIoctl(fd, DRM_IOCTL_MODE_GETPROPERTY, &prop)
//内核态
DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPERTY, drm_mode_getproperty_ioctl, 0)
4.13.2.3. connector初始化
以下代码基于renesas rcar平台分析
//rcar-du/rcar_lvds.c
static int rcar_lvds_attach(struct drm_bridge *bridge)
{
struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
struct drm_connector *connector = &lvds->connector;
struct drm_encoder *encoder = bridge->encoder;
int ret;
/* If we have a next bridge just attach it. */
if (lvds->next_bridge)
return drm_bridge_attach(bridge->encoder, lvds->next_bridge,
bridge);
/* Otherwise if we have a panel, create a connector. */
if (!lvds->panel)
return 0;
ret = drm_connector_init(bridge->dev, connector, &rcar_lvds_conn_funcs,
DRM_MODE_CONNECTOR_LVDS);
if (ret < 0)
return ret;
drm_connector_helper_add(connector, &rcar_lvds_conn_helper_funcs);
ret = drm_connector_attach_encoder(connector, encoder);
if (ret < 0)
return ret;
return drm_panel_attach(lvds->panel, connector);
}
static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
.attach = rcar_lvds_attach,
.detach = rcar_lvds_detach,
.enable = rcar_lvds_enable,
.disable = rcar_lvds_disable,
.mode_fixup = rcar_lvds_mode_fixup,
.mode_set = rcar_lvds_mode_set,
};
static int rcar_lvds_probe(struct platform_device *pdev)
{
const struct soc_device_attribute *attr;
struct rcar_lvds *lvds;
struct resource *mem;
int ret;
lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
if (lvds == NULL)
return -ENOMEM;
platform_set_drvdata(pdev, lvds);
lvds->dev = &pdev->dev;
lvds->info = of_device_get_match_data(&pdev->dev);
attr = soc_device_match(lvds_quirk_matches);
if (attr)
lvds->info = attr->data;
ret = rcar_lvds_parse_dt(lvds);
if (ret < 0)
return ret;
lvds->bridge.driver_private = lvds;
lvds->bridge.funcs = &rcar_lvds_bridge_ops;
lvds->bridge.of_node = pdev->dev.of_node;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
lvds->mmio = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(lvds->mmio))
return PTR_ERR(lvds->mmio);
ret = rcar_lvds_get_clocks(lvds);
if (ret < 0)
return ret;
lvds->rstc = devm_reset_control_get(&pdev->dev, NULL);
if (IS_ERR(lvds->rstc)) {
dev_err(&pdev->dev, "failed to get cpg reset\n");
return PTR_ERR(lvds->rstc);
}
drm_bridge_add(&lvds->bridge);
return 0;
}
static struct platform_driver rcar_lvds_platform_driver = {
.probe = rcar_lvds_probe,
.remove = rcar_lvds_remove,
.driver = {
.name = "rcar-lvds",
.of_match_table = rcar_lvds_of_table,
},
};