Kernel clients¶

This library provides support for clients running in the kernel like fbdev and bootsplash.

GEM drivers which provide a GEM based dumb buffer with a virtual address are supported.

structdrm_client_funcs¶

DRM client callbacks

Definition

struct drm_client_funcs {  struct module *owner;  void (*unregister)(struct drm_client_dev *client);  int (*restore)(struct drm_client_dev *client);  int (*hotplug)(struct drm_client_dev *client);};

Members

owner

The module owner

unregister

Called whendrm_device is unregistered. The client should respond byreleasing its resources usingdrm_client_release().

This callback is optional.

restore

Called on drm_lastclose(). The first client instance in the list thatreturns zero gets the privilege to restore and no more clients arecalled. This callback is not called afterunregister has been called.

Note that the core does not guarantee exclusion against concurrentdrm_open(). Clients need to ensure this themselves, for example byusing drm_master_internal_acquire() anddrm_master_internal_release().

This callback is optional.

hotplug

Called ondrm_kms_helper_hotplug_event().This callback is not called afterunregister has been called.

This callback is optional.

structdrm_client_dev¶

DRM client instance

Definition

struct drm_client_dev {  struct drm_device *dev;  const char *name;  struct list_head list;  const struct drm_client_funcs *funcs;  struct drm_file *file;  struct mutex modeset_mutex;  struct drm_mode_set *modesets;};

Members

dev

DRM device

name

Name of the client.

list

List of all clients of a DRM device, linked intodrm_device.clientlist. Protected bydrm_device.clientlist_mutex.

funcs

DRM client functions (optional)

file

DRM file

modeset_mutex

Protectsmodesets.

modesets

CRTC configurations

structdrm_client_buffer¶

DRM client buffer

Definition

struct drm_client_buffer {  struct drm_client_dev *client;  u32 handle;  u32 pitch;  struct drm_gem_object *gem;  void *vaddr;  struct drm_framebuffer *fb;};

Members

client

DRM client

handle

Buffer handle

pitch

Buffer pitch

gem

GEM object backing this buffer

vaddr

Virtual address for the buffer

fb

DRM framebuffer

drm_client_for_each_modeset(modeset,client)¶

Iterate over client modesets

Parameters

modeset

drm_mode_set loop cursor

client

DRM client

drm_client_for_each_connector_iter(connector,iter)¶

connector_list iterator macro

Parameters

connector

structdrm_connector pointer used as cursor

iter

structdrm_connector_list_iter

Description

This iterates the connectors that are useable for internal clients (excludeswriteback connectors).

For more info seedrm_for_each_connector_iter().

intdrm_client_init(structdrm_device * dev, structdrm_client_dev * client, const char * name, const structdrm_client_funcs * funcs)¶

Initialise a DRM client

Parameters

structdrm_device*dev

DRM device

structdrm_client_dev*client

DRM client

constchar*name

Client name

conststructdrm_client_funcs*funcs

DRM client functions (optional)

Description

This initialises the client and opens adrm_file.Usedrm_client_register() to complete the process.The caller needs to hold a reference ondev before calling this function.The client is freed when thedrm_device is unregistered. Seedrm_client_release().

Return

Zero on success or negative error code on failure.

voiddrm_client_register(structdrm_client_dev * client)¶

Register client

Parameters

structdrm_client_dev*client

DRM client

Description

Add the client to thedrm_device client list to activate its callbacks.client must be initialized by a call todrm_client_init(). Afterdrm_client_register() it is no longer permissible to calldrm_client_release()directly (outside the unregister callback), instead cleanup will happenautomatically on driver unload.

voiddrm_client_release(structdrm_client_dev * client)¶

Release DRM client resources

Parameters

structdrm_client_dev*client

DRM client

Description

Releases resources by closing thedrm_file that was opened bydrm_client_init().It is called automatically if thedrm_client_funcs.unregister callback is _not_ set.

This function should only be called from the unregister callback. An exceptionis fbdev which cannot free the buffer if userspace has open file descriptors.

Note

Clients cannot initiate a release by themselves. This is done to keep the code simple.The driver has to be unloaded before the client can be unloaded.

voiddrm_client_dev_hotplug(structdrm_device * dev)¶

Send hotplug event to clients

Parameters

structdrm_device*dev

DRM device

Description

This function calls thedrm_client_funcs.hotplug callback on the attached clients.

drm_kms_helper_hotplug_event() calls this function, so drivers that use itdon’t need to call this function themselves.

void *drm_client_buffer_vmap(structdrm_client_buffer * buffer)¶

Map DRM client buffer into address space

Parameters

structdrm_client_buffer*buffer

DRM client buffer

Description

This function maps a client buffer into kernel address space. If thebuffer is already mapped, it returns the mapping’s address.

Client buffer mappings are not ref’counted. Each call todrm_client_buffer_vmap() should be followed by a call todrm_client_buffer_vunmap(); or the client buffer should be mappedthroughout its lifetime.

Return

The mapped memory’s address

voiddrm_client_buffer_vunmap(structdrm_client_buffer * buffer)¶

Unmap DRM client buffer

Parameters

structdrm_client_buffer*buffer

DRM client buffer

Description

This function removes a client buffer’s memory mapping. Calling thisfunction is only required by clients that manage their buffer mappingsby themselves.

structdrm_client_buffer *drm_client_framebuffer_create(structdrm_client_dev * client, u32 width, u32 height, u32 format)¶

Create a client framebuffer

Parameters

structdrm_client_dev*client

DRM client

u32width

Framebuffer width

u32height

Framebuffer height

u32format

Buffer format

Description

This function creates adrm_client_buffer which consists of adrm_framebuffer backed by a dumb buffer.Calldrm_client_framebuffer_delete() to free the buffer.

Return

Pointer to a client buffer or an error pointer on failure.

voiddrm_client_framebuffer_delete(structdrm_client_buffer * buffer)¶

Delete a client framebuffer

Parameters

structdrm_client_buffer*buffer

DRM client buffer (can be NULL)

intdrm_client_framebuffer_flush(structdrm_client_buffer * buffer, structdrm_rect * rect)¶

Manually flush client framebuffer

Parameters

structdrm_client_buffer*buffer

DRM client buffer (can be NULL)

structdrm_rect*rect

Damage rectangle (if NULL flushes all)

Description

This callsdrm_framebuffer_funcs->dirty (if present) to flush buffer changesfor drivers that need it.

Return

Zero on success or negative error code on failure.

intdrm_client_modeset_probe(structdrm_client_dev * client, unsigned int width, unsigned int height)¶

Probe for displays

Parameters

structdrm_client_dev*client

DRM client

unsignedintwidth

Maximum display mode width (optional)

unsignedintheight

Maximum display mode height (optional)

Description

This function sets up display pipelines for enabled connectors and stores theconfig in the client’s modeset array.

Return

Zero on success or negative error code on failure.

booldrm_client_rotation(structdrm_mode_set * modeset, unsigned int * rotation)¶

Check the initial rotation value

Parameters

structdrm_mode_set*modeset

DRM modeset

unsignedint*rotation

Returned rotation value

Description

This function checks if the primary plane inmodeset can hw rotateto match the rotation needed on its connector.

Note

Currently only 0 and 180 degrees are supported.

Return

True if the plane can do the rotation, false otherwise.

intdrm_client_modeset_check(structdrm_client_dev * client)¶

Check modeset configuration

Parameters

structdrm_client_dev*client

DRM client

Description

Check modeset configuration.

Return

Zero on success or negative error code on failure.

intdrm_client_modeset_commit_locked(structdrm_client_dev * client)¶

Force commit CRTC configuration

Parameters

structdrm_client_dev*client

DRM client

Description

Commit modeset configuration to crtcs without checking if there is a DRMmaster. The assumption is that the caller already holds an internal DRMmaster reference acquired with drm_master_internal_acquire().

Return

Zero on success or negative error code on failure.

intdrm_client_modeset_commit(structdrm_client_dev * client)¶

Commit CRTC configuration

Parameters

structdrm_client_dev*client

DRM client

Description

Commit modeset configuration to crtcs.

Return

Zero on success or negative error code on failure.

intdrm_client_modeset_dpms(structdrm_client_dev * client, int mode)¶

Set DPMS mode

Parameters

structdrm_client_dev*client

DRM client

intmode

DPMS mode

Note

For atomic driversmode is reduced to on/off.

Return

Zero on success or negative error code on failure.