xref: /openbmc/linux/Documentation/gpu/i915.rst (revision 76a4f7cc)
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_dp.c
187   :doc: Display Refresh Rate Switching (DRRS)
188
189.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp.c
190   :functions: intel_dp_set_drrs_state
191
192.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp.c
193   :functions: intel_edp_drrs_enable
194
195.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp.c
196   :functions: intel_edp_drrs_disable
197
198.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp.c
199   :functions: intel_edp_drrs_invalidate
200
201.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp.c
202   :functions: intel_edp_drrs_flush
203
204.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp.c
205   :functions: intel_dp_drrs_init
206
207DPIO
208----
209
210.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpio_phy.c
211   :doc: DPIO
212
213DMC Firmware Support
214--------------------
215
216.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc.c
217   :doc: DMC Firmware Support
218
219.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc.c
220   :internal:
221
222Video BIOS Table (VBT)
223----------------------
224
225.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c
226   :doc: Video BIOS Table (VBT)
227
228.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c
229   :internal:
230
231.. kernel-doc:: drivers/gpu/drm/i915/display/intel_vbt_defs.h
232   :internal:
233
234Display clocks
235--------------
236
237.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c
238   :doc: CDCLK / RAWCLK
239
240.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c
241   :internal:
242
243Display PLLs
244------------
245
246.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c
247   :doc: Display PLLs
248
249.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c
250   :internal:
251
252.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.h
253   :internal:
254
255Display State Buffer
256--------------------
257
258.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c
259   :doc: DSB
260
261.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c
262   :internal:
263
264Memory Management and Command Submission
265========================================
266
267This sections covers all things related to the GEM implementation in the
268i915 driver.
269
270Intel GPU Basics
271----------------
272
273An Intel GPU has multiple engines. There are several engine types.
274
275- RCS engine is for rendering 3D and performing compute, this is named
276  `I915_EXEC_RENDER` in user space.
277- BCS is a blitting (copy) engine, this is named `I915_EXEC_BLT` in user
278  space.
279- VCS is a video encode and decode engine, this is named `I915_EXEC_BSD`
280  in user space
281- VECS is video enhancement engine, this is named `I915_EXEC_VEBOX` in user
282  space.
283- The enumeration `I915_EXEC_DEFAULT` does not refer to specific engine;
284  instead it is to be used by user space to specify a default rendering
285  engine (for 3D) that may or may not be the same as RCS.
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 atleast) 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 atleast) 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
477Microcontrollers
478================
479
480Starting from gen9, three microcontrollers are available on the HW: the
481graphics microcontroller (GuC), the HEVC/H.265 microcontroller (HuC) and the
482display microcontroller (DMC). The driver is responsible for loading the
483firmwares on the microcontrollers; the GuC and HuC firmwares are transferred
484to WOPCM using the DMA engine, while the DMC firmware is written through MMIO.
485
486WOPCM
487-----
488
489WOPCM Layout
490~~~~~~~~~~~~
491
492.. kernel-doc:: drivers/gpu/drm/i915/intel_wopcm.c
493   :doc: WOPCM Layout
494
495GuC
496---
497
498.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
499   :doc: GuC
500
501GuC Firmware Layout
502~~~~~~~~~~~~~~~~~~~
503
504.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_uc_fw_abi.h
505   :doc: Firmware Layout
506
507GuC Memory Management
508~~~~~~~~~~~~~~~~~~~~~
509
510.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
511   :doc: GuC Memory Management
512.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
513   :functions: intel_guc_allocate_vma
514
515
516GuC-specific firmware loader
517~~~~~~~~~~~~~~~~~~~~~~~~~~~~
518
519.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
520   :internal:
521
522GuC-based command submission
523~~~~~~~~~~~~~~~~~~~~~~~~~~~~
524
525.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
526   :doc: GuC-based command submission
527
528GuC ABI
529~~~~~~~~~~~~~~~~~~~~~~~~~~~~
530
531.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_messages_abi.h
532.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_communication_mmio_abi.h
533.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
534.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
535
536HuC
537---
538.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
539   :doc: HuC
540.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
541   :functions: intel_huc_auth
542
543HuC Memory Management
544~~~~~~~~~~~~~~~~~~~~~
545
546.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
547   :doc: HuC Memory Management
548
549HuC Firmware Layout
550~~~~~~~~~~~~~~~~~~~
551The HuC FW layout is the same as the GuC one, see `GuC Firmware Layout`_
552
553DMC
554---
555See `DMC Firmware Support`_
556
557Tracing
558=======
559
560This sections covers all things related to the tracepoints implemented
561in the i915 driver.
562
563i915_ppgtt_create and i915_ppgtt_release
564----------------------------------------
565
566.. kernel-doc:: drivers/gpu/drm/i915/i915_trace.h
567   :doc: i915_ppgtt_create and i915_ppgtt_release tracepoints
568
569i915_context_create and i915_context_free
570-----------------------------------------
571
572.. kernel-doc:: drivers/gpu/drm/i915/i915_trace.h
573   :doc: i915_context_create and i915_context_free tracepoints
574
575Perf
576====
577
578Overview
579--------
580.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
581   :doc: i915 Perf Overview
582
583Comparison with Core Perf
584-------------------------
585.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
586   :doc: i915 Perf History and Comparison with Core Perf
587
588i915 Driver Entry Points
589------------------------
590
591This section covers the entrypoints exported outside of i915_perf.c to
592integrate with drm/i915 and to handle the `DRM_I915_PERF_OPEN` ioctl.
593
594.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
595   :functions: i915_perf_init
596.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
597   :functions: i915_perf_fini
598.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
599   :functions: i915_perf_register
600.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
601   :functions: i915_perf_unregister
602.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
603   :functions: i915_perf_open_ioctl
604.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
605   :functions: i915_perf_release
606.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
607   :functions: i915_perf_add_config_ioctl
608.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
609   :functions: i915_perf_remove_config_ioctl
610
611i915 Perf Stream
612----------------
613
614This section covers the stream-semantics-agnostic structures and functions
615for representing an i915 perf stream FD and associated file operations.
616
617.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
618   :functions: i915_perf_stream
619.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
620   :functions: i915_perf_stream_ops
621
622.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
623   :functions: read_properties_unlocked
624.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
625   :functions: i915_perf_open_ioctl_locked
626.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
627   :functions: i915_perf_destroy_locked
628.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
629   :functions: i915_perf_read
630.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
631   :functions: i915_perf_ioctl
632.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
633   :functions: i915_perf_enable_locked
634.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
635   :functions: i915_perf_disable_locked
636.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
637   :functions: i915_perf_poll
638.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
639   :functions: i915_perf_poll_locked
640
641i915 Perf Observation Architecture Stream
642-----------------------------------------
643
644.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
645   :functions: i915_oa_ops
646
647.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
648   :functions: i915_oa_stream_init
649.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
650   :functions: i915_oa_read
651.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
652   :functions: i915_oa_stream_enable
653.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
654   :functions: i915_oa_stream_disable
655.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
656   :functions: i915_oa_wait_unlocked
657.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
658   :functions: i915_oa_poll_wait
659
660Other i915 Perf Internals
661-------------------------
662
663This section simply includes all other currently documented i915 perf internals,
664in no particular order, but may include some more minor utilities or platform
665specific details than found in the more high-level sections.
666
667.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
668   :internal:
669   :no-identifiers:
670       i915_perf_init
671       i915_perf_fini
672       i915_perf_register
673       i915_perf_unregister
674       i915_perf_open_ioctl
675       i915_perf_release
676       i915_perf_add_config_ioctl
677       i915_perf_remove_config_ioctl
678       read_properties_unlocked
679       i915_perf_open_ioctl_locked
680       i915_perf_destroy_locked
681       i915_perf_read i915_perf_ioctl
682       i915_perf_enable_locked
683       i915_perf_disable_locked
684       i915_perf_poll i915_perf_poll_locked
685       i915_oa_stream_init i915_oa_read
686       i915_oa_stream_enable
687       i915_oa_stream_disable
688       i915_oa_wait_unlocked
689       i915_oa_poll_wait
690
691Style
692=====
693
694The drm/i915 driver codebase has some style rules in addition to (and, in some
695cases, deviating from) the kernel coding style.
696
697Register macro definition style
698-------------------------------
699
700The style guide for ``i915_reg.h``.
701
702.. kernel-doc:: drivers/gpu/drm/i915/i915_reg.h
703   :doc: The i915 register macro definition style guide
704