接前一篇文章：DRM全解析 —— ADD_FB2（4）
本文参考以下博文：
特此致谢！
上一回讲解了drm_mode_addfb2函数中的第一步暨第一个函数drm_core_check_feature。本回继续对于drm_mode_addfb2函数往下进行解析。为了便于理解，再次贴出其代码，在drivers/gpu/drm/drm_framebuffer.c中，如下：
/**
* drm_mode_addfb2 - add an FB to the graphics configuration
* @dev: drm device for the ioctl
* @data: data pointer for the ioctl
* @file_priv: drm file for the ioctl call
*
* Add a new FB to the specified CRTC, given a user request with format. This is
* the 2nd version of the addfb ioctl, which supports multi-planar framebuffers
* and uses fourcc codes as pixel format specifiers.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_mode_addfb2(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_mode_fb_cmd2 *r = data;
struct drm_framebuffer *fb;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EOPNOTSUPP;
fb = drm_internal_framebuffer_create(dev, r, file_priv);
if (IS_ERR(fb))
return PTR_ERR(fb);
drm_dbg_kms(dev, "[FB:%d]\n", fb->base.id);
r->fb_id = fb->base.id;
/* Transfer ownership to the filp for reaping on close */
mutex_lock(&file_priv->fbs_lock);
list_add(&fb->filp_head, &file_priv->fbs);
mutex_unlock(&file_priv->fbs_lock);
return 0;
}
第二步是调用drm_internal_framebuffer_create函数创建内部的framebuffer。drm_internal_framebuffer_create函数在drivers/gpu/drm/drm_framebuffer.c中，代码如下：
struct drm_framebuffer *
drm_internal_framebuffer_create(struct drm_device *dev,
const struct drm_mode_fb_cmd2 *r,
struct drm_file *file_priv)
{
struct drm_mode_config *config = &dev->mode_config;
struct drm_framebuffer *fb;
int ret;
if (r->flags & ~(DRM_MODE_FB_INTERLACED | DRM_MODE_FB_MODIFIERS)) {
drm_dbg_kms(dev, "bad framebuffer flags 0x%08x\n", r->flags);
return ERR_PTR(-EINVAL);
}
if ((config->min_width > r->width) || (r->width > config->max_width)) {
drm_dbg_kms(dev, "bad framebuffer width %d, should be >= %d && <= %d\n",
r->width, config->min_width, config->max_width);
return ERR_PTR(-EINVAL);
}
if ((config->min_height > r->height) || (r->height > config->max_height)) {
drm_dbg_kms(dev, "bad framebuffer height %d, should be >= %d && <= %d\n",
r->height, config->min_height, config->max_height);
return ERR_PTR(-EINVAL);
}
if (r->flags & DRM_MODE_FB_MODIFIERS &&
dev->mode_config.fb_modifiers_not_supported) {
drm_dbg_kms(dev, "driver does not support fb modifiers\n");
return ERR_PTR(-EINVAL);
}
ret = framebuffer_check(dev, r);
if (ret)
return ERR_PTR(ret);
fb = dev->mode_config.funcs->fb_create(dev, file_priv, r);
if (IS_ERR(fb)) {
drm_dbg_kms(dev, "could not create framebuffer\n");
return fb;
}
return fb;
}
EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_internal_framebuffer_create);一上来先是获得配置（mode_config），代码片断如下：
struct drm_mode_config *config = &dev->mode_config;struct drm_mode_config的定义在include/drm/drm_mode_config.h中，代码如下：
/**
* struct drm_mode_config - Mode configuration control structure
* @min_width: minimum fb pixel width on this device
* @min_height: minimum fb pixel height on this device
* @max_width: maximum fb pixel width on this device
* @max_height: maximum fb pixel height on this device
* @funcs: core driver provided mode setting functions
* @fb_base: base address of the framebuffer
* @poll_enabled: track polling support for this device
* @poll_running: track polling status for this device
* @delayed_event: track delayed poll uevent deliver for this device
* @output_poll_work: delayed work for polling in process context
* @preferred_depth: preferred RBG pixel depth, used by fb helpers
* @prefer_shadow: hint to userspace to prefer shadow-fb rendering
* @cursor_width: hint to userspace for max cursor width
* @cursor_height: hint to userspace for max cursor height
* @helper_private: mid-layer private data
*
* Core mode resource tracking structure. All CRTC, encoders, and connectors
* enumerated by the driver are added here, as are global properties. Some
* global restrictions are also here, e.g. dimension restrictions.
*
* Framebuffer sizes refer to the virtual screen that can be displayed by
* the CRTC. This can be different from the physical resolution programmed.
* The minimum width and height, stored in @min_width and @min_height,
* describe the smallest size of the framebuffer. It correlates to the
* minimum programmable resolution.
* The maximum width, stored in @max_width, is typically limited by the
* maximum pitch between two adjacent scanlines. The maximum height, stored
* in @max_height, is usually only limited by the amount of addressable video
* memory. For hardware that has no real maximum, drivers should pick a
* reasonable default.
*
* See also @DRM_SHADOW_PLANE_MAX_WIDTH and @DRM_SHADOW_PLANE_MAX_HEIGHT.
*/
struct drm_mode_config {
/**
* @mutex:
*
* This is the big scary modeset BKL which protects everything that
* isn't protect otherwise. Scope is unclear and fuzzy, try to remove
* anything from under its protection and move it into more well-scoped
* locks.
*
* The one important thing this protects is the use of @acquire_ctx.
*/
struct mutex mutex;
/**
* @connection_mutex:
*
* This protects connector state and the connector to encoder to CRTC
* routing chain.
*
* For atomic drivers specifically this protects &drm_connector.state.
*/
struct drm_modeset_lock connection_mutex;
/**
* @acquire_ctx:
*
* Global implicit acquire context used by atomic drivers for legacy
* IOCTLs. Deprecated, since implicit locking contexts make it
* impossible to use driver-private &struct drm_modeset_lock. Users of
* this must hold @mutex.
*/
struct drm_modeset_acquire_ctx *acquire_ctx;
/**
* @idr_mutex:
*
* Mutex for KMS ID allocation and management. Protects both @object_idr
* and @tile_idr.
*/
struct mutex idr_mutex;
/**
* @object_idr:
*
* Main KMS ID tracking object. Use this idr for all IDs, fb, crtc,
* connector, modes - just makes life easier to have only one.
*/
struct idr object_idr;
/**
* @tile_idr:
*
* Use this idr for allocating new IDs for tiled sinks like use in some
* high-res DP MST screens.
*/
struct idr tile_idr;
/** @fb_lock: Mutex to protect fb the global @fb_list and @num_fb. */
struct mutex fb_lock;
/** @num_fb: Number of entries on @fb_list. */
int num_fb;
/** @fb_list: List of all &struct drm_framebuffer. */
struct list_head fb_list;
/**
* @connector_list_lock: Protects @num_connector and
* @connector_list and @connector_free_list.
*/
spinlock_t connector_list_lock;
/**
* @num_connector: Number of connectors on this device. Protected by
* @connector_list_lock.
*/
int num_connector;
/**
* @connector_ida: ID allocator for connector indices.
*/
struct ida connector_ida;
/**
* @connector_list:
*
* List of connector objects linked with &drm_connector.head. Protected
* by @connector_list_lock. Only use drm_for_each_connector_iter() and
* &struct drm_connector_list_iter to walk this list.
*/
struct list_head connector_list;
/**
* @connector_free_list:
*
* List of connector objects linked with &drm_connector.free_head.
* Protected by @connector_list_lock. Used by
* drm_for_each_connector_iter() and
* &struct drm_connector_list_iter to savely free connectors using
* @connector_free_work.
*/
struct llist_head connector_free_list;
/**
* @connector_free_work: Work to clean up @connector_free_list.
*/
struct work_struct connector_free_work;
/**
* @num_encoder:
*
* Number of encoders on this device. This is invariant over the
* lifetime of a device and hence doesn't need any locks.
*/
int num_encoder;
/**
* @encoder_list:
*
* List of encoder objects linked with &drm_encoder.head. This is
* invariant over the lifetime of a device and hence doesn't need any
* locks.
*/
struct list_head encoder_list;
/**
* @num_total_plane:
*
* Number of universal (i.e. with primary/curso) planes on this device.
* This is invariant over the lifetime of a device and hence doesn't
* need any locks.
*/
int num_total_plane;
/**
* @plane_list:
*
* List of plane objects linked with &drm_plane.head. This is invariant
* over the lifetime of a device and hence doesn't need any locks.
*/
struct list_head plane_list;
/**
* @num_crtc:
*
* Number of CRTCs on this device linked with &drm_crtc.head. This is invariant over the lifetime
* of a device and hence doesn't need any locks.
*/
int num_crtc;
/**
* @crtc_list:
*
* List of CRTC objects linked with &drm_crtc.head. This is invariant
* over the lifetime of a device and hence doesn't need any locks.
*/
struct list_head crtc_list;
/**
* @property_list:
*
* List of property type objects linked with &drm_property.head. This is
* invariant over the lifetime of a device and hence doesn't need any
* locks.
*/
struct list_head property_list;
/**
* @privobj_list:
*
* List of private objects linked with &drm_private_obj.head. This is
* invariant over the lifetime of a device and hence doesn't need any
* locks.
*/
struct list_head privobj_list;
int min_width, min_height;
int max_width, max_height;
const struct drm_mode_config_funcs *funcs;
resource_size_t fb_base;
/* output poll support */
bool poll_enabled;
bool poll_running;
bool delayed_event;
struct delayed_work output_poll_work;
/**
* @blob_lock:
*
* Mutex for blob property allocation and management, protects
* @property_blob_list and &drm_file.blobs.
*/
struct mutex blob_lock;
/**
* @property_blob_list:
*
* List of all the blob property objects linked with
* &drm_property_blob.head. Protected by @blob_lock.
*/
struct list_head property_blob_list;
/* pointers to standard properties */
/**
* @edid_property: Default connector property to hold the EDID of the
* currently connected sink, if any.
*/
struct drm_property *edid_property;
/**
* @dpms_property: Default connector property to control the
* connector's DPMS state.
*/
struct drm_property *dpms_property;
/**
* @path_property: Default connector property to hold the DP MST path
* for the port.
*/
struct drm_property *path_property;
/**
* @tile_property: Default connector property to store the tile
* position of a tiled screen, for sinks which need to be driven with
* multiple CRTCs.
*/
struct drm_property *tile_property;
/**
* @link_status_property: Default connector property for link status
* of a connector
*/
struct drm_property *link_status_property;
/**
* @plane_type_property: Default plane property to differentiate
* CURSOR, PRIMARY and OVERLAY legacy uses of planes.
*/
struct drm_property *plane_type_property;
/**
* @prop_src_x: Default atomic plane property for the plane source
* position in the connected &drm_framebuffer.
*/
struct drm_property *prop_src_x;
/**
* @prop_src_y: Default atomic plane property for the plane source
* position in the connected &drm_framebuffer.
*/
struct drm_property *prop_src_y;
/**
* @prop_src_w: Default atomic plane property for the plane source
* position in the connected &drm_framebuffer.
*/
struct drm_property *prop_src_w;
/**
* @prop_src_h: Default atomic plane property for the plane source
* position in the connected &drm_framebuffer.
*/
struct drm_property *prop_src_h;
/**
* @prop_crtc_x: Default atomic plane property for the plane destination
* position in the &drm_crtc is being shown on.
*/
struct drm_property *prop_crtc_x;
/**
* @prop_crtc_y: Default atomic plane property for the plane destination
* position in the &drm_crtc is being shown on.
*/
struct drm_property *prop_crtc_y;
/**
* @prop_crtc_w: Default atomic plane property for the plane destination
* position in the &drm_crtc is being shown on.
*/
struct drm_property *prop_crtc_w;
/**
* @prop_crtc_h: Default atomic plane property for the plane destination
* position in the &drm_crtc is being shown on.
*/
struct drm_property *prop_crtc_h;
/**
* @prop_fb_id: Default atomic plane property to specify the
* &drm_framebuffer.
*/
struct drm_property *prop_fb_id;
/**
* @prop_in_fence_fd: Sync File fd representing the incoming fences
* for a Plane.
*/
struct drm_property *prop_in_fence_fd;
/**
* @prop_out_fence_ptr: Sync File fd pointer representing the
* outgoing fences for a CRTC. Userspace should provide a pointer to a
* value of type s32, and then cast that pointer to u64.
*/
struct drm_property *prop_out_fence_ptr;
/**
* @prop_crtc_id: Default atomic plane property to specify the
* &drm_crtc.
*/
struct drm_property *prop_crtc_id;
/**
* @prop_fb_damage_clips: Optional plane property to mark damaged
* regions on the plane in framebuffer coordinates of the framebuffer
* attached to the plane.
*
* The layout of blob data is simply an array of &drm_mode_rect. Unlike
* plane src coordinates, damage clips are not in 16.16 fixed point.
*/
struct drm_property *prop_fb_damage_clips;
/**
* @prop_active: Default atomic CRTC property to control the active
* state, which is the simplified implementation for DPMS in atomic
* drivers.
*/
struct drm_property *prop_active;
/**
* @prop_mode_id: Default atomic CRTC property to set the mode for a
* CRTC. A 0 mode implies that the CRTC is entirely disabled - all
* connectors must be of and active must be set to disabled, too.
*/
struct drm_property *prop_mode_id;
/**
* @prop_vrr_enabled: Default atomic CRTC property to indicate
* whether variable refresh rate should be enabled on the CRTC.
*/
struct drm_property *prop_vrr_enabled;
/**
* @dvi_i_subconnector_property: Optional DVI-I property to
* differentiate between analog or digital mode.
*/
struct drm_property *dvi_i_subconnector_property;
/**
* @dvi_i_select_subconnector_property: Optional DVI-I property to
* select between analog or digital mode.
*/
struct drm_property *dvi_i_select_subconnector_property;
/**
* @dp_subconnector_property: Optional DP property to differentiate
* between different DP downstream port types.
*/
struct drm_property *dp_subconnector_property;
/**
* @tv_subconnector_property: Optional TV property to differentiate
* between different TV connector types.
*/
struct drm_property *tv_subconnector_property;
/**
* @tv_select_subconnector_property: Optional TV property to select
* between different TV connector types.
*/
struct drm_property *tv_select_subconnector_property;
/**
* @tv_mode_property: Optional TV property to select
* the output TV mode.
*/
struct drm_property *tv_mode_property;
/**
* @tv_left_margin_property: Optional TV property to set the left
* margin (expressed in pixels).
*/
struct drm_property *tv_left_margin_property;
/**
* @tv_right_margin_property: Optional TV property to set the right
* margin (expressed in pixels).
*/
struct drm_property *tv_right_margin_property;
/**
* @tv_top_margin_property: Optional TV property to set the right
* margin (expressed in pixels).
*/
struct drm_property *tv_top_margin_property;
/**
* @tv_bottom_margin_property: Optional TV property to set the right
* margin (expressed in pixels).
*/
struct drm_property *tv_bottom_margin_property;
/**
* @tv_brightness_property: Optional TV property to set the
* brightness.
*/
struct drm_property *tv_brightness_property;
/**
* @tv_contrast_property: Optional TV property to set the
* contrast.
*/
struct drm_property *tv_contrast_property;
/**
* @tv_flicker_reduction_property: Optional TV property to control the
* flicker reduction mode.
*/
struct drm_property *tv_flicker_reduction_property;
/**
* @tv_overscan_property: Optional TV property to control the overscan
* setting.
*/
struct drm_property *tv_overscan_property;
/**
* @tv_saturation_property: Optional TV property to set the
* saturation.
*/
struct drm_property *tv_saturation_property;
/**
* @tv_hue_property: Optional TV property to set the hue.
*/
struct drm_property *tv_hue_property;
/**
* @scaling_mode_property: Optional connector property to control the
* upscaling, mostly used for built-in panels.
*/
struct drm_property *scaling_mode_property;
/**
* @aspect_ratio_property: Optional connector property to control the
* HDMI infoframe aspect ratio setting.
*/
struct drm_property *aspect_ratio_property;
/**
* @content_type_property: Optional connector property to control the
* HDMI infoframe content type setting.
*/
struct drm_property *content_type_property;
/**
* @degamma_lut_property: Optional CRTC property to set the LUT used to
* convert the framebuffer's colors to linear gamma.
*/
struct drm_property *degamma_lut_property;
/**
* @degamma_lut_size_property: Optional CRTC property for the size of
* the degamma LUT as supported by the driver (read-only).
*/
struct drm_property *degamma_lut_size_property;
/**
* @ctm_property: Optional CRTC property to set the
* matrix used to convert colors after the lookup in the
* degamma LUT.
*/
struct drm_property *ctm_property;
/**
* @gamma_lut_property: Optional CRTC property to set the LUT used to
* convert the colors, after the CTM matrix, to the gamma space of the
* connected screen.
*/
struct drm_property *gamma_lut_property;
/**
* @gamma_lut_size_property: Optional CRTC property for the size of the
* gamma LUT as supported by the driver (read-only).
*/
struct drm_property *gamma_lut_size_property;
/**
* @suggested_x_property: Optional connector property with a hint for
* the position of the output on the host's screen.
*/
struct drm_property *suggested_x_property;
/**
* @suggested_y_property: Optional connector property with a hint for
* the position of the output on the host's screen.
*/
struct drm_property *suggested_y_property;
/**
* @non_desktop_property: Optional connector property with a hint
* that device isn't a standard display, and the console/desktop,
* should not be displayed on it.
*/
struct drm_property *non_desktop_property;
/**
* @panel_orientation_property: Optional connector property indicating
* how the lcd-panel is mounted inside the casing (e.g. normal or
* upside-down).
*/
struct drm_property *panel_orientation_property;
/**
* @writeback_fb_id_property: Property for writeback connectors, storing
* the ID of the output framebuffer.
* See also: drm_writeback_connector_init()
*/
struct drm_property *writeback_fb_id_property;
/**
* @writeback_pixel_formats_property: Property for writeback connectors,
* storing an array of the supported pixel formats for the writeback
* engine (read-only).
* See also: drm_writeback_connector_init()
*/
struct drm_property *writeback_pixel_formats_property;
/**
* @writeback_out_fence_ptr_property: Property for writeback connectors,
* fd pointer representing the outgoing fences for a writeback
* connector. Userspace should provide a pointer to a value of type s32,
* and then cast that pointer to u64.
* See also: drm_writeback_connector_init()
*/
struct drm_property *writeback_out_fence_ptr_property;
/**
* @hdr_output_metadata_property: Connector property containing hdr
* metatada. This will be provided by userspace compositors based
* on HDR content
*/
struct drm_property *hdr_output_metadata_property;
/**
* @content_protection_property: DRM ENUM property for content
* protection. See drm_connector_attach_content_protection_property().
*/
struct drm_property *content_protection_property;
/**
* @hdcp_content_type_property: DRM ENUM property for type of
* Protected Content.
*/
struct drm_property *hdcp_content_type_property;
/* dumb ioctl parameters */
uint32_t preferred_depth, prefer_shadow;
/**
* @prefer_shadow_fbdev:
*
* Hint to framebuffer emulation to prefer shadow-fb rendering.
*/
bool prefer_shadow_fbdev;
/**
* @quirk_addfb_prefer_xbgr_30bpp:
*
* Special hack for legacy ADDFB to keep nouveau userspace happy. Should
* only ever be set by the nouveau kernel driver.
*/
bool quirk_addfb_prefer_xbgr_30bpp;
/**
* @quirk_addfb_prefer_host_byte_order:
*
* When set to true drm_mode_addfb() will pick host byte order
* pixel_format when calling drm_mode_addfb2(). This is how
* drm_mode_addfb() should have worked from day one. It
* didn't though, so we ended up with quirks in both kernel
* and userspace drivers to deal with the broken behavior.
* Simply fixing drm_mode_addfb() unconditionally would break
* these drivers, so add a quirk bit here to allow drivers
* opt-in.
*/
bool quirk_addfb_prefer_host_byte_order;
/**
* @async_page_flip: Does this device support async flips on the primary
* plane?
*/
bool async_page_flip;
/**
* @fb_modifiers_not_supported:
*
* When this flag is set, the DRM device will not expose modifier
* support to userspace. This is only used by legacy drivers that infer
* the buffer layout through heuristics without using modifiers. New
* drivers shall not set fhis flag.
*/
bool fb_modifiers_not_supported;
/**
* @normalize_zpos:
*
* If true the drm core will call drm_atomic_normalize_zpos() as part of
* atomic mode checking from drm_atomic_helper_check()
*/
bool normalize_zpos;
/**
* @modifiers_property: Plane property to list support modifier/format
* combination.
*/
struct drm_property *modifiers_property;
/* cursor size */
uint32_t cursor_width, cursor_height;
/**
* @suspend_state:
*
* Atomic state when suspended.
* Set by drm_mode_config_helper_suspend() and cleared by
* drm_mode_config_helper_resume().
*/
struct drm_atomic_state *suspend_state;
const struct drm_mode_config_helper_funcs *helper_private;
};这是一个相当庞大的结构体，和进程的那个struct task_struct都有一拼了。在此我们暂不做深入分析，后边用到哪个成员再针对其进行具体讲解。
前文已提到，dev代表struct drm_device *dev（设备实例），dev->mode_config的意思是dev设备对应的mode_config。实际上dev->mode_config也是不同的显卡对应不同的mode_config的。这里仍以笔者实际接触过的两款显卡Intel和AMD为例进行说明。
- Intel i915
Intel i915对应的dev->mode_config在drivers/gpu/drm/i915/display/intel_display.c中的intel_mode_config_init函数中赋值，代码如下：
static void intel_mode_config_init(struct drm_i915_private *i915)
{
struct drm_mode_config *mode_config = &i915->drm.mode_config;
drm_mode_config_init(&i915->drm);
INIT_LIST_HEAD(&i915->global_obj_list);
mode_config->min_width = 0;
mode_config->min_height = 0;
mode_config->preferred_depth = 24;
mode_config->prefer_shadow = 1;
mode_config->funcs = &intel_mode_funcs;
mode_config->helper_private = &intel_mode_config_funcs;
mode_config->async_page_flip = HAS_ASYNC_FLIPS(i915);
/*
* Maximum framebuffer dimensions, chosen to match
* the maximum render engine surface size on gen4+.
*/
if (DISPLAY_VER(i915) >= 7) {
mode_config->max_width = 16384;
mode_config->max_height = 16384;
} else if (DISPLAY_VER(i915) >= 4) {
mode_config->max_width = 8192;
mode_config->max_height = 8192;
} else if (DISPLAY_VER(i915) == 3) {
mode_config->max_width = 4096;
mode_config->max_height = 4096;
} else {
mode_config->max_width = 2048;
mode_config->max_height = 2048;
}
if (IS_I845G(i915) || IS_I865G(i915)) {
mode_config->cursor_width = IS_I845G(i915) ? 64 : 512;
mode_config->cursor_height = 1023;
} else if (IS_I830(i915) || IS_I85X(i915) ||
IS_I915G(i915) || IS_I915GM(i915)) {
mode_config->cursor_width = 64;
mode_config->cursor_height = 64;
} else {
mode_config->cursor_width = 256;
mode_config->cursor_height = 256;
}
}- AMD Raedon
AMD显卡有两款驱动：Raedon和AMDGPU。
先说Raedon驱动。Raedon对应的dev->mode_config在drivers/gpu/drm/radeon/radeon_display.c中的radeon_modeset_init函数中赋值，代码如下：
int radeon_modeset_init(struct radeon_device *rdev)
{
int i;
int ret;
drm_mode_config_init(rdev->ddev);
rdev->mode_info.mode_config_initialized = true;
rdev->ddev->mode_config.funcs = &radeon_mode_funcs;
if (radeon_use_pflipirq == 2 && rdev->family >= CHIP_R600)
rdev->ddev->mode_config.async_page_flip = true;
if (ASIC_IS_DCE5(rdev)) {
rdev->ddev->mode_config.max_width = 16384;
rdev->ddev->mode_config.max_height = 16384;
} else if (ASIC_IS_AVIVO(rdev)) {
rdev->ddev->mode_config.max_width = 8192;
rdev->ddev->mode_config.max_height = 8192;
} else {
rdev->ddev->mode_config.max_width = 4096;
rdev->ddev->mode_config.max_height = 4096;
}
rdev->ddev->mode_config.preferred_depth = 24;
rdev->ddev->mode_config.prefer_shadow = 1;
rdev->ddev->mode_config.fb_modifiers_not_supported = true;
rdev->ddev->mode_config.fb_base = rdev->mc.aper_base;
ret = radeon_modeset_create_props(rdev);
if (ret) {
return ret;
}
/* init i2c buses */
radeon_i2c_init(rdev);
/* check combios for a valid hardcoded EDID - Sun servers */
if (!rdev->is_atom_bios) {
/* check for hardcoded EDID in BIOS */
radeon_combios_check_hardcoded_edid(rdev);
}
/* allocate crtcs */
for (i = 0; i < rdev->num_crtc; i++) {
radeon_crtc_init(rdev->ddev, i);
}
/* okay we should have all the bios connectors */
ret = radeon_setup_enc_conn(rdev->ddev);
if (!ret) {
return ret;
}
/* init dig PHYs, disp eng pll */
if (rdev->is_atom_bios) {
radeon_atom_encoder_init(rdev);
radeon_atom_disp_eng_pll_init(rdev);
}
/* initialize hpd */
radeon_hpd_init(rdev);
/* setup afmt */
radeon_afmt_init(rdev);
radeon_fbdev_init(rdev);
drm_kms_helper_poll_init(rdev->ddev);
/* do pm late init */
ret = radeon_pm_late_init(rdev);
return 0;
}- AMD AMDGPU
再来看AMDGPU驱动。AMDGPU对应的dev->mode_config在drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c中的amdgpu_vkms_sw_init函数中赋值，代码如下：
static int amdgpu_vkms_sw_init(void *handle)
{
int r, i;
struct amdgpu_device *adev = (struct amdgpu_device *)handle;
adev->amdgpu_vkms_output = kcalloc(adev->mode_info.num_crtc,
sizeof(struct amdgpu_vkms_output), GFP_KERNEL);
if (!adev->amdgpu_vkms_output)
return -ENOMEM;
adev_to_drm(adev)->max_vblank_count = 0;
adev_to_drm(adev)->mode_config.funcs = &amdgpu_vkms_mode_funcs;
adev_to_drm(adev)->mode_config.max_width = XRES_MAX;
adev_to_drm(adev)->mode_config.max_height = YRES_MAX;
adev_to_drm(adev)->mode_config.preferred_depth = 24;
adev_to_drm(adev)->mode_config.prefer_shadow = 1;
adev_to_drm(adev)->mode_config.fb_base = adev->gmc.aper_base;
adev_to_drm(adev)->mode_config.fb_modifiers_not_supported = true;
r = amdgpu_display_modeset_create_props(adev);
if (r)
return r;
/* allocate crtcs, encoders, connectors */
for (i = 0; i < adev->mode_info.num_crtc; i++) {
r = amdgpu_vkms_output_init(adev_to_drm(adev), &adev->amdgpu_vkms_output[i], i);
if (r)
return r;
}
drm_kms_helper_poll_init(adev_to_drm(adev));
adev->mode_info.mode_config_initialized = true;
return 0;
}在得到了mode_config之后，drm_internal_framebuffer_create函数将基于此mode_config进行参数判断以及功能实现。更多内容请看下回。