xref: /linux/Documentation/gpu/i915.rst (revision 0678df8271820bcf8fb4f877129f05d68a237de4)
1===========================
2 drm/i915 Intel GFX Driver
3===========================
4
5The drm/i915 driver supports all (with the exception of some very early
6models) integrated GFX chipsets with both Intel display and rendering
7blocks. This excludes a set of SoC platforms with an SGX rendering unit,
8those have basic support through the gma500 drm driver.
9
10Core Driver Infrastructure
11==========================
12
13This section covers core driver infrastructure used by both the display
14and the GEM parts of the driver.
15
16Runtime Power Management
17------------------------
18
19.. kernel-doc:: drivers/gpu/drm/i915/intel_runtime_pm.c
20   :doc: runtime pm
21
22.. kernel-doc:: drivers/gpu/drm/i915/intel_runtime_pm.c
23   :internal:
24
25.. kernel-doc:: drivers/gpu/drm/i915/intel_uncore.c
26   :internal:
27
28Interrupt Handling
29------------------
30
31.. kernel-doc:: drivers/gpu/drm/i915/i915_irq.c
32   :doc: interrupt handling
33
34.. kernel-doc:: drivers/gpu/drm/i915/i915_irq.c
35   :functions: intel_irq_init intel_irq_init_hw intel_hpd_init
36
37.. kernel-doc:: drivers/gpu/drm/i915/i915_irq.c
38   :functions: intel_runtime_pm_disable_interrupts
39
40.. kernel-doc:: drivers/gpu/drm/i915/i915_irq.c
41   :functions: intel_runtime_pm_enable_interrupts
42
43Intel GVT-g Guest Support(vGPU)
44-------------------------------
45
46.. kernel-doc:: drivers/gpu/drm/i915/i915_vgpu.c
47   :doc: Intel GVT-g guest support
48
49.. kernel-doc:: drivers/gpu/drm/i915/i915_vgpu.c
50   :internal:
51
52Intel GVT-g Host Support(vGPU device model)
53-------------------------------------------
54
55.. kernel-doc:: drivers/gpu/drm/i915/intel_gvt.c
56   :doc: Intel GVT-g host support
57
58.. kernel-doc:: drivers/gpu/drm/i915/intel_gvt.c
59   :internal:
60
61Workarounds
62-----------
63
64.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_workarounds.c
65   :doc: Hardware workarounds
66
67Display Hardware Handling
68=========================
69
70This section covers everything related to the display hardware including
71the mode setting infrastructure, plane, sprite and cursor handling and
72display, output probing and related topics.
73
74Mode Setting Infrastructure
75---------------------------
76
77The i915 driver is thus far the only DRM driver which doesn't use the
78common DRM helper code to implement mode setting sequences. Thus it has
79its own tailor-made infrastructure for executing a display configuration
80change.
81
82Frontbuffer Tracking
83--------------------
84
85.. kernel-doc:: drivers/gpu/drm/i915/display/intel_frontbuffer.c
86   :doc: frontbuffer tracking
87
88.. kernel-doc:: drivers/gpu/drm/i915/display/intel_frontbuffer.h
89   :internal:
90
91.. kernel-doc:: drivers/gpu/drm/i915/display/intel_frontbuffer.c
92   :internal:
93
94Display FIFO Underrun Reporting
95-------------------------------
96
97.. kernel-doc:: drivers/gpu/drm/i915/display/intel_fifo_underrun.c
98   :doc: fifo underrun handling
99
100.. kernel-doc:: drivers/gpu/drm/i915/display/intel_fifo_underrun.c
101   :internal:
102
103Plane Configuration
104-------------------
105
106This section covers plane configuration and composition with the primary
107plane, sprites, cursors and overlays. This includes the infrastructure
108to do atomic vsync'ed updates of all this state and also tightly coupled
109topics like watermark setup and computation, framebuffer compression and
110panel self refresh.
111
112Atomic Plane Helpers
113--------------------
114
115.. kernel-doc:: drivers/gpu/drm/i915/display/intel_atomic_plane.c
116   :doc: atomic plane helpers
117
118.. kernel-doc:: drivers/gpu/drm/i915/display/intel_atomic_plane.c
119   :internal:
120
121Asynchronous Page Flip
122----------------------
123
124.. kernel-doc:: drivers/gpu/drm/i915/display/intel_display.c
125   :doc: asynchronous flip implementation
126
127Output Probing
128--------------
129
130This section covers output probing and related infrastructure like the
131hotplug interrupt storm detection and mitigation code. Note that the
132i915 driver still uses most of the common DRM helper code for output
133probing, so those sections fully apply.
134
135Hotplug
136-------
137
138.. kernel-doc:: drivers/gpu/drm/i915/display/intel_hotplug.c
139   :doc: Hotplug
140
141.. kernel-doc:: drivers/gpu/drm/i915/display/intel_hotplug.c
142   :internal:
143
144High Definition Audio
145---------------------
146
147.. kernel-doc:: drivers/gpu/drm/i915/display/intel_audio.c
148   :doc: High Definition Audio over HDMI and Display Port
149
150.. kernel-doc:: drivers/gpu/drm/i915/display/intel_audio.c
151   :internal:
152
153.. kernel-doc:: include/drm/i915_component.h
154   :internal:
155
156Intel HDMI LPE Audio Support
157----------------------------
158
159.. kernel-doc:: drivers/gpu/drm/i915/display/intel_lpe_audio.c
160   :doc: LPE Audio integration for HDMI or DP playback
161
162.. kernel-doc:: drivers/gpu/drm/i915/display/intel_lpe_audio.c
163   :internal:
164
165Panel Self Refresh PSR (PSR/SRD)
166--------------------------------
167
168.. kernel-doc:: drivers/gpu/drm/i915/display/intel_psr.c
169   :doc: Panel Self Refresh (PSR/SRD)
170
171.. kernel-doc:: drivers/gpu/drm/i915/display/intel_psr.c
172   :internal:
173
174Frame Buffer Compression (FBC)
175------------------------------
176
177.. kernel-doc:: drivers/gpu/drm/i915/display/intel_fbc.c
178   :doc: Frame Buffer Compression (FBC)
179
180.. kernel-doc:: drivers/gpu/drm/i915/display/intel_fbc.c
181   :internal:
182
183Display Refresh Rate Switching (DRRS)
184-------------------------------------
185
186.. kernel-doc:: drivers/gpu/drm/i915/display/intel_drrs.c
187   :doc: Display Refresh Rate Switching (DRRS)
188
189.. kernel-doc:: drivers/gpu/drm/i915/display/intel_drrs.c
190   :internal:
191
192DPIO
193----
194
195.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpio_phy.c
196   :doc: DPIO
197
198DMC Firmware Support
199--------------------
200
201.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc.c
202   :doc: DMC Firmware Support
203
204.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc.c
205   :internal:
206
207Video BIOS Table (VBT)
208----------------------
209
210.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c
211   :doc: Video BIOS Table (VBT)
212
213.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c
214   :internal:
215
216.. kernel-doc:: drivers/gpu/drm/i915/display/intel_vbt_defs.h
217   :internal:
218
219Display clocks
220--------------
221
222.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c
223   :doc: CDCLK / RAWCLK
224
225.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c
226   :internal:
227
228Display PLLs
229------------
230
231.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c
232   :doc: Display PLLs
233
234.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c
235   :internal:
236
237.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.h
238   :internal:
239
240Display State Buffer
241--------------------
242
243.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c
244   :doc: DSB
245
246.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c
247   :internal:
248
249GT Programming
250==============
251
252Multicast/Replicated (MCR) Registers
253------------------------------------
254
255.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gt_mcr.c
256   :doc: GT Multicast/Replicated (MCR) Register Support
257
258.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gt_mcr.c
259   :internal:
260
261Memory Management and Command Submission
262========================================
263
264This sections covers all things related to the GEM implementation in the
265i915 driver.
266
267Intel GPU Basics
268----------------
269
270An Intel GPU has multiple engines. There are several engine types:
271
272- Render Command Streamer (RCS). An engine for rendering 3D and
273  performing compute.
274- Blitting Command Streamer (BCS). An engine for performing blitting and/or
275  copying operations.
276- Video Command Streamer. An engine used for video encoding and decoding. Also
277  sometimes called 'BSD' in hardware documentation.
278- Video Enhancement Command Streamer (VECS). An engine for video enhancement.
279  Also sometimes called 'VEBOX' in hardware documentation.
280- Compute Command Streamer (CCS). An engine that has access to the media and
281  GPGPU pipelines, but not the 3D pipeline.
282- Graphics Security Controller (GSCCS). A dedicated engine for internal
283  communication with GSC controller on security related tasks like
284  High-bandwidth Digital Content Protection (HDCP), Protected Xe Path (PXP),
285  and HuC firmware authentication.
286
287The Intel GPU family is a family of integrated GPU's using Unified
288Memory Access. For having the GPU "do work", user space will feed the
289GPU batch buffers via one of the ioctls `DRM_IOCTL_I915_GEM_EXECBUFFER2`
290or `DRM_IOCTL_I915_GEM_EXECBUFFER2_WR`. Most such batchbuffers will
291instruct the GPU to perform work (for example rendering) and that work
292needs memory from which to read and memory to which to write. All memory
293is encapsulated within GEM buffer objects (usually created with the ioctl
294`DRM_IOCTL_I915_GEM_CREATE`). An ioctl providing a batchbuffer for the GPU
295to create will also list all GEM buffer objects that the batchbuffer reads
296and/or writes. For implementation details of memory management see
297`GEM BO Management Implementation Details`_.
298
299The i915 driver allows user space to create a context via the ioctl
300`DRM_IOCTL_I915_GEM_CONTEXT_CREATE` which is identified by a 32-bit
301integer. Such a context should be viewed by user-space as -loosely-
302analogous to the idea of a CPU process of an operating system. The i915
303driver guarantees that commands issued to a fixed context are to be
304executed so that writes of a previously issued command are seen by
305reads of following commands. Actions issued between different contexts
306(even if from the same file descriptor) are NOT given that guarantee
307and the only way to synchronize across contexts (even from the same
308file descriptor) is through the use of fences. At least as far back as
309Gen4, also have that a context carries with it a GPU HW context;
310the HW context is essentially (most of at least) the state of a GPU.
311In addition to the ordering guarantees, the kernel will restore GPU
312state via HW context when commands are issued to a context, this saves
313user space the need to restore (most of at least) the GPU state at the
314start of each batchbuffer. The non-deprecated ioctls to submit batchbuffer
315work can pass that ID (in the lower bits of drm_i915_gem_execbuffer2::rsvd1)
316to identify what context to use with the command.
317
318The GPU has its own memory management and address space. The kernel
319driver maintains the memory translation table for the GPU. For older
320GPUs (i.e. those before Gen8), there is a single global such translation
321table, a global Graphics Translation Table (GTT). For newer generation
322GPUs each context has its own translation table, called Per-Process
323Graphics Translation Table (PPGTT). Of important note, is that although
324PPGTT is named per-process it is actually per context. When user space
325submits a batchbuffer, the kernel walks the list of GEM buffer objects
326used by the batchbuffer and guarantees that not only is the memory of
327each such GEM buffer object resident but it is also present in the
328(PP)GTT. If the GEM buffer object is not yet placed in the (PP)GTT,
329then it is given an address. Two consequences of this are: the kernel
330needs to edit the batchbuffer submitted to write the correct value of
331the GPU address when a GEM BO is assigned a GPU address and the kernel
332might evict a different GEM BO from the (PP)GTT to make address room
333for another GEM BO. Consequently, the ioctls submitting a batchbuffer
334for execution also include a list of all locations within buffers that
335refer to GPU-addresses so that the kernel can edit the buffer correctly.
336This process is dubbed relocation.
337
338Locking Guidelines
339------------------
340
341.. note::
342   This is a description of how the locking should be after
343   refactoring is done. Does not necessarily reflect what the locking
344   looks like while WIP.
345
346#. All locking rules and interface contracts with cross-driver interfaces
347   (dma-buf, dma_fence) need to be followed.
348
349#. No struct_mutex anywhere in the code
350
351#. dma_resv will be the outermost lock (when needed) and ww_acquire_ctx
352   is to be hoisted at highest level and passed down within i915_gem_ctx
353   in the call chain
354
355#. While holding lru/memory manager (buddy, drm_mm, whatever) locks
356   system memory allocations are not allowed
357
358	* Enforce this by priming lockdep (with fs_reclaim). If we
359	  allocate memory while holding these looks we get a rehash
360	  of the shrinker vs. struct_mutex saga, and that would be
361	  real bad.
362
363#. Do not nest different lru/memory manager locks within each other.
364   Take them in turn to update memory allocations, relying on the object’s
365   dma_resv ww_mutex to serialize against other operations.
366
367#. The suggestion for lru/memory managers locks is that they are small
368   enough to be spinlocks.
369
370#. All features need to come with exhaustive kernel selftests and/or
371   IGT tests when appropriate
372
373#. All LMEM uAPI paths need to be fully restartable (_interruptible()
374   for all locks/waits/sleeps)
375
376	* Error handling validation through signal injection.
377	  Still the best strategy we have for validating GEM uAPI
378          corner cases.
379	  Must be excessively used in the IGT, and we need to check
380	  that we really have full path coverage of all error cases.
381
382	* -EDEADLK handling with ww_mutex
383
384GEM BO Management Implementation Details
385----------------------------------------
386
387.. kernel-doc:: drivers/gpu/drm/i915/i915_vma_types.h
388   :doc: Virtual Memory Address
389
390Buffer Object Eviction
391----------------------
392
393This section documents the interface functions for evicting buffer
394objects to make space available in the virtual gpu address spaces. Note
395that this is mostly orthogonal to shrinking buffer objects caches, which
396has the goal to make main memory (shared with the gpu through the
397unified memory architecture) available.
398
399.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_evict.c
400   :internal:
401
402Buffer Object Memory Shrinking
403------------------------------
404
405This section documents the interface function for shrinking memory usage
406of buffer object caches. Shrinking is used to make main memory
407available. Note that this is mostly orthogonal to evicting buffer
408objects, which has the goal to make space in gpu virtual address spaces.
409
410.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
411   :internal:
412
413Batchbuffer Parsing
414-------------------
415
416.. kernel-doc:: drivers/gpu/drm/i915/i915_cmd_parser.c
417   :doc: batch buffer command parser
418
419.. kernel-doc:: drivers/gpu/drm/i915/i915_cmd_parser.c
420   :internal:
421
422User Batchbuffer Execution
423--------------------------
424
425.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_context_types.h
426
427.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
428   :doc: User command execution
429
430Scheduling
431----------
432.. kernel-doc:: drivers/gpu/drm/i915/i915_scheduler_types.h
433   :functions: i915_sched_engine
434
435Logical Rings, Logical Ring Contexts and Execlists
436--------------------------------------------------
437
438.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_execlists_submission.c
439   :doc: Logical Rings, Logical Ring Contexts and Execlists
440
441Global GTT views
442----------------
443
444.. kernel-doc:: drivers/gpu/drm/i915/i915_vma_types.h
445   :doc: Global GTT views
446
447.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_gtt.c
448   :internal:
449
450GTT Fences and Swizzling
451------------------------
452
453.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
454   :internal:
455
456Global GTT Fence Handling
457~~~~~~~~~~~~~~~~~~~~~~~~~
458
459.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
460   :doc: fence register handling
461
462Hardware Tiling and Swizzling Details
463~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
464
465.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
466   :doc: tiling swizzling details
467
468Object Tiling IOCTLs
469--------------------
470
471.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_tiling.c
472   :internal:
473
474.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_tiling.c
475   :doc: buffer object tiling
476
477Protected Objects
478-----------------
479
480.. kernel-doc:: drivers/gpu/drm/i915/pxp/intel_pxp.c
481   :doc: PXP
482
483.. kernel-doc:: drivers/gpu/drm/i915/pxp/intel_pxp_types.h
484
485Microcontrollers
486================
487
488Starting from gen9, three microcontrollers are available on the HW: the
489graphics microcontroller (GuC), the HEVC/H.265 microcontroller (HuC) and the
490display microcontroller (DMC). The driver is responsible for loading the
491firmwares on the microcontrollers; the GuC and HuC firmwares are transferred
492to WOPCM using the DMA engine, while the DMC firmware is written through MMIO.
493
494WOPCM
495-----
496
497WOPCM Layout
498~~~~~~~~~~~~
499
500.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_wopcm.c
501   :doc: WOPCM Layout
502
503GuC
504---
505
506.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
507   :doc: GuC
508
509.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.h
510
511GuC Firmware Layout
512~~~~~~~~~~~~~~~~~~~
513
514.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_uc_fw_abi.h
515   :doc: Firmware Layout
516
517GuC Memory Management
518~~~~~~~~~~~~~~~~~~~~~
519
520.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
521   :doc: GuC Memory Management
522.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
523   :functions: intel_guc_allocate_vma
524
525
526GuC-specific firmware loader
527~~~~~~~~~~~~~~~~~~~~~~~~~~~~
528
529.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
530   :internal:
531
532GuC-based command submission
533~~~~~~~~~~~~~~~~~~~~~~~~~~~~
534
535.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
536   :doc: GuC-based command submission
537
538GuC ABI
539~~~~~~~~~~~~~~~~~~~~~~~~~~~~
540
541.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_messages_abi.h
542.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_communication_mmio_abi.h
543.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
544.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
545.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
546
547HuC
548---
549.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
550   :doc: HuC
551.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
552   :functions: intel_huc_auth
553
554HuC Memory Management
555~~~~~~~~~~~~~~~~~~~~~
556
557.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
558   :doc: HuC Memory Management
559
560HuC Firmware Layout
561~~~~~~~~~~~~~~~~~~~
562The HuC FW layout is the same as the GuC one, see `GuC Firmware Layout`_
563
564DMC
565---
566See `DMC Firmware Support`_
567
568Tracing
569=======
570
571This sections covers all things related to the tracepoints implemented
572in the i915 driver.
573
574i915_ppgtt_create and i915_ppgtt_release
575----------------------------------------
576
577.. kernel-doc:: drivers/gpu/drm/i915/i915_trace.h
578   :doc: i915_ppgtt_create and i915_ppgtt_release tracepoints
579
580i915_context_create and i915_context_free
581-----------------------------------------
582
583.. kernel-doc:: drivers/gpu/drm/i915/i915_trace.h
584   :doc: i915_context_create and i915_context_free tracepoints
585
586Perf
587====
588
589Overview
590--------
591.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
592   :doc: i915 Perf Overview
593
594Comparison with Core Perf
595-------------------------
596.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
597   :doc: i915 Perf History and Comparison with Core Perf
598
599i915 Driver Entry Points
600------------------------
601
602This section covers the entrypoints exported outside of i915_perf.c to
603integrate with drm/i915 and to handle the `DRM_I915_PERF_OPEN` ioctl.
604
605.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
606   :functions: i915_perf_init
607.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
608   :functions: i915_perf_fini
609.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
610   :functions: i915_perf_register
611.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
612   :functions: i915_perf_unregister
613.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
614   :functions: i915_perf_open_ioctl
615.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
616   :functions: i915_perf_release
617.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
618   :functions: i915_perf_add_config_ioctl
619.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
620   :functions: i915_perf_remove_config_ioctl
621
622i915 Perf Stream
623----------------
624
625This section covers the stream-semantics-agnostic structures and functions
626for representing an i915 perf stream FD and associated file operations.
627
628.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
629   :functions: i915_perf_stream
630.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
631   :functions: i915_perf_stream_ops
632
633.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
634   :functions: read_properties_unlocked
635.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
636   :functions: i915_perf_open_ioctl_locked
637.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
638   :functions: i915_perf_destroy_locked
639.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
640   :functions: i915_perf_read
641.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
642   :functions: i915_perf_ioctl
643.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
644   :functions: i915_perf_enable_locked
645.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
646   :functions: i915_perf_disable_locked
647.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
648   :functions: i915_perf_poll
649.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
650   :functions: i915_perf_poll_locked
651
652i915 Perf Observation Architecture Stream
653-----------------------------------------
654
655.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
656   :functions: i915_oa_ops
657
658.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
659   :functions: i915_oa_stream_init
660.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
661   :functions: i915_oa_read
662.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
663   :functions: i915_oa_stream_enable
664.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
665   :functions: i915_oa_stream_disable
666.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
667   :functions: i915_oa_wait_unlocked
668.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
669   :functions: i915_oa_poll_wait
670
671Other i915 Perf Internals
672-------------------------
673
674This section simply includes all other currently documented i915 perf internals,
675in no particular order, but may include some more minor utilities or platform
676specific details than found in the more high-level sections.
677
678.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
679   :internal:
680   :no-identifiers:
681       i915_perf_init
682       i915_perf_fini
683       i915_perf_register
684       i915_perf_unregister
685       i915_perf_open_ioctl
686       i915_perf_release
687       i915_perf_add_config_ioctl
688       i915_perf_remove_config_ioctl
689       read_properties_unlocked
690       i915_perf_open_ioctl_locked
691       i915_perf_destroy_locked
692       i915_perf_read i915_perf_ioctl
693       i915_perf_enable_locked
694       i915_perf_disable_locked
695       i915_perf_poll i915_perf_poll_locked
696       i915_oa_stream_init i915_oa_read
697       i915_oa_stream_enable
698       i915_oa_stream_disable
699       i915_oa_wait_unlocked
700       i915_oa_poll_wait
701
702Style
703=====
704
705The drm/i915 driver codebase has some style rules in addition to (and, in some
706cases, deviating from) the kernel coding style.
707
708Register macro definition style
709-------------------------------
710
711The style guide for ``i915_reg.h``.
712
713.. kernel-doc:: drivers/gpu/drm/i915/i915_reg.h
714   :doc: The i915 register macro definition style guide
715
716.. _i915-usage-stats:
717
718i915 DRM client usage stats implementation
719==========================================
720
721The drm/i915 driver implements the DRM client usage stats specification as
722documented in :ref:`drm-client-usage-stats`.
723
724Example of the output showing the implemented key value pairs and entirety of
725the currently possible format options:
726
727::
728
729      pos:    0
730      flags:  0100002
731      mnt_id: 21
732      drm-driver: i915
733      drm-pdev:   0000:00:02.0
734      drm-client-id:      7
735      drm-engine-render:  9288864723 ns
736      drm-engine-copy:    2035071108 ns
737      drm-engine-video:   0 ns
738      drm-engine-capacity-video:   2
739      drm-engine-video-enhance:   0 ns
740
741Possible `drm-engine-` key names are: `render`, `copy`, `video` and
742`video-enhance`.
743