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.
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struct drm_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 when
drm_device
is unregistered. The client should respond by releasing its resources usingdrm_client_release()
.This callback is optional.
restore
Called on drm_lastclose(). The first client instance in the list that returns zero gets the privilege to restore and no more clients are called. This callback is not called after unregister has been called.
Note that the core does not guarantee exclusion against concurrent
drm_open()
. Clients need to ensure this themselves, for example by using drm_master_internal_acquire() and drm_master_internal_release().This callback is optional.
hotplug
Called on
drm_kms_helper_hotplug_event()
. This callback is not called after unregister has been called.This callback is optional.
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struct drm_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;
bool hotplug_failed;
};
Members
dev
DRM device
name
Name of the client.
list
List of all clients of a DRM device, linked into
drm_device.clientlist
. Protected bydrm_device.clientlist_mutex
.funcs
DRM client functions (optional)
file
DRM file
modeset_mutex
Protects modesets.
modesets
CRTC configurations
hotplug_failed
Set by client hotplug helpers if the hotplugging failed before. It is usually not tried again.
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struct drm_client_buffer¶
DRM client buffer
Definition:
struct drm_client_buffer {
struct drm_client_dev *client;
u32 pitch;
struct drm_gem_object *gem;
struct iosys_map map;
struct drm_framebuffer *fb;
};
Members
client
DRM client
pitch
Buffer pitch
gem
GEM object backing this buffer
FIXME: The dependency on GEM here isn’t required, we could convert the driver handle to a dma-buf instead and use the backend-agnostic dma-buf vmap support instead. This would require that the handle2fd prime ioctl is reworked to pull the fd_install step out of the driver backend hooks, to make that final step optional for internal users.
map
Virtual address for the buffer
fb
DRM framebuffer
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drm_client_for_each_modeset¶
drm_client_for_each_modeset (modeset, client)
Iterate over client modesets
Parameters
modeset
drm_mode_set
loop cursorclient
DRM client
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drm_client_for_each_connector_iter¶
drm_client_for_each_connector_iter (connector, iter)
connector_list iterator macro
Parameters
connector
struct drm_connector
pointer used as cursoriter
Description
This iterates the connectors that are useable for internal clients (excludes writeback connectors).
For more info see drm_for_each_connector_iter()
.
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int drm_client_init(struct drm_device *dev, struct drm_client_dev *client, const char *name, const struct drm_client_funcs *funcs)¶
Initialise a DRM client
Parameters
struct drm_device *dev
DRM device
struct drm_client_dev *client
DRM client
const char *name
Client name
const struct drm_client_funcs *funcs
DRM client functions (optional)
Description
This initialises the client and opens a drm_file
.
Use drm_client_register()
to complete the process.
The caller needs to hold a reference on dev before calling this function.
The client is freed when the drm_device
is unregistered. See drm_client_release()
.
Return
Zero on success or negative error code on failure.
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void drm_client_register(struct drm_client_dev *client)¶
Register client
Parameters
struct drm_client_dev *client
DRM client
Description
Add the client to the drm_device
client list to activate its callbacks.
client must be initialized by a call to drm_client_init()
. After
drm_client_register()
it is no longer permissible to call drm_client_release()
directly (outside the unregister callback), instead cleanup will happen
automatically on driver unload.
Registering a client generates a hotplug event that allows the client to set up its display from pre-existing outputs. The client must have initialized its state to able to handle the hotplug event successfully.
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void drm_client_release(struct drm_client_dev *client)¶
Release DRM client resources
Parameters
struct drm_client_dev *client
DRM client
Description
Releases resources by closing the drm_file
that was opened by drm_client_init()
.
It is called automatically if the drm_client_funcs.unregister
callback is _not_ set.
This function should only be called from the unregister callback. An exception is 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.
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void drm_client_dev_unregister(struct drm_device *dev)¶
Unregister clients
Parameters
struct drm_device *dev
DRM device
Description
This function releases all clients by calling each client’s
drm_client_funcs.unregister
callback. The callback function
is responsibe for releaseing all resources including the client
itself.
The helper drm_dev_unregister()
calls this function. Drivers
that use it don’t need to call this function themselves.
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void drm_client_dev_hotplug(struct drm_device *dev)¶
Send hotplug event to clients
Parameters
struct drm_device *dev
DRM device
Description
This function calls the drm_client_funcs.hotplug
callback on the attached clients.
drm_kms_helper_hotplug_event()
calls this function, so drivers that use it
don’t need to call this function themselves.
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int drm_client_buffer_vmap_local(struct drm_client_buffer *buffer, struct iosys_map *map_copy)¶
Map DRM client buffer into address space
Parameters
struct drm_client_buffer *buffer
DRM client buffer
struct iosys_map *map_copy
Returns the mapped memory’s address
Description
This function maps a client buffer into kernel address space. If the buffer is already mapped, it returns the existing mapping’s address.
Client buffer mappings are not ref’counted. Each call to
drm_client_buffer_vmap_local()
should be closely followed by a call to
drm_client_buffer_vunmap_local()
. See drm_client_buffer_vmap()
for
long-term mappings.
The returned address is a copy of the internal value. In contrast to other vmap interfaces, you don’t need it for the client’s vunmap function. So you can modify it at will during blit and draw operations.
Return
0 on success, or a negative errno code otherwise.
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void drm_client_buffer_vunmap_local(struct drm_client_buffer *buffer)¶
Unmap DRM client buffer
Parameters
struct drm_client_buffer *buffer
DRM client buffer
Description
This function removes a client buffer’s memory mapping established
with drm_client_buffer_vunmap_local()
. Calling this function is only
required by clients that manage their buffer mappings by themselves.
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int drm_client_buffer_vmap(struct drm_client_buffer *buffer, struct iosys_map *map_copy)¶
Map DRM client buffer into address space
Parameters
struct drm_client_buffer *buffer
DRM client buffer
struct iosys_map *map_copy
Returns the mapped memory’s address
Description
This function maps a client buffer into kernel address space. If the buffer is already mapped, it returns the existing mapping’s address.
Client buffer mappings are not ref’counted. Each call to
drm_client_buffer_vmap()
should be followed by a call to
drm_client_buffer_vunmap()
; or the client buffer should be mapped
throughout its lifetime.
The returned address is a copy of the internal value. In contrast to other vmap interfaces, you don’t need it for the client’s vunmap function. So you can modify it at will during blit and draw operations.
Return
0 on success, or a negative errno code otherwise.
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void drm_client_buffer_vunmap(struct drm_client_buffer *buffer)¶
Unmap DRM client buffer
Parameters
struct drm_client_buffer *buffer
DRM client buffer
Description
This function removes a client buffer’s memory mapping. Calling this function is only required by clients that manage their buffer mappings by themselves.
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struct drm_client_buffer *drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)¶
Create a client framebuffer
Parameters
struct drm_client_dev *client
DRM client
u32 width
Framebuffer width
u32 height
Framebuffer height
u32 format
Buffer format
Description
This function creates a drm_client_buffer
which consists of a
drm_framebuffer
backed by a dumb buffer.
Call drm_client_framebuffer_delete()
to free the buffer.
Return
Pointer to a client buffer or an error pointer on failure.
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void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)¶
Delete a client framebuffer
Parameters
struct drm_client_buffer *buffer
DRM client buffer (can be NULL)
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int drm_client_framebuffer_flush(struct drm_client_buffer *buffer, struct drm_rect *rect)¶
Manually flush client framebuffer
Parameters
struct drm_client_buffer *buffer
DRM client buffer (can be NULL)
struct drm_rect *rect
Damage rectangle (if NULL flushes all)
Description
This calls drm_framebuffer_funcs->dirty
(if present) to flush buffer changes
for drivers that need it.
Return
Zero on success or negative error code on failure.
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int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width, unsigned int height)¶
Probe for displays
Parameters
struct drm_client_dev *client
DRM client
unsigned int width
Maximum display mode width (optional)
unsigned int height
Maximum display mode height (optional)
Description
This function sets up display pipelines for enabled connectors and stores the config in the client’s modeset array.
Return
Zero on success or negative error code on failure.
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bool drm_client_rotation(struct drm_mode_set *modeset, unsigned int *rotation)¶
Check the initial rotation value
Parameters
struct drm_mode_set *modeset
DRM modeset
unsigned int *rotation
Returned rotation value
Description
This function checks if the primary plane in modeset can hw rotate to 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.
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int drm_client_modeset_check(struct drm_client_dev *client)¶
Check modeset configuration
Parameters
struct drm_client_dev *client
DRM client
Description
Check modeset configuration.
Return
Zero on success or negative error code on failure.
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int drm_client_modeset_commit_locked(struct drm_client_dev *client)¶
Force commit CRTC configuration
Parameters
struct drm_client_dev *client
DRM client
Description
Commit modeset configuration to crtcs without checking if there is a DRM master. The assumption is that the caller already holds an internal DRM master reference acquired with drm_master_internal_acquire().
Return
Zero on success or negative error code on failure.
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int drm_client_modeset_commit(struct drm_client_dev *client)¶
Commit CRTC configuration
Parameters
struct drm_client_dev *client
DRM client
Description
Commit modeset configuration to crtcs.
Return
Zero on success or negative error code on failure.
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int drm_client_modeset_dpms(struct drm_client_dev *client, int mode)¶
Set DPMS mode
Parameters
struct drm_client_dev *client
DRM client
int mode
DPMS mode
Note
For atomic drivers mode is reduced to on/off.
Return
Zero on success or negative error code on failure.