xref: /linux/Documentation/gpu/i915.rst (revision a36e9f5cfe9eb3a1dce8769c7058251c42705357)
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/intel/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
207DMC wakelock support
208--------------------
209
210.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc_wl.c
211   :doc: DMC wakelock support
212
213Video BIOS Table (VBT)
214----------------------
215
216.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c
217   :doc: Video BIOS Table (VBT)
218
219.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c
220   :internal:
221
222.. kernel-doc:: drivers/gpu/drm/i915/display/intel_vbt_defs.h
223   :internal:
224
225Display clocks
226--------------
227
228.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c
229   :doc: CDCLK / RAWCLK
230
231.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c
232   :internal:
233
234Display PLLs
235------------
236
237.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c
238   :doc: Display PLLs
239
240.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c
241   :internal:
242
243.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.h
244   :internal:
245
246Display State Buffer
247--------------------
248
249.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c
250   :doc: DSB
251
252.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c
253   :internal:
254
255GT Programming
256==============
257
258Multicast/Replicated (MCR) Registers
259------------------------------------
260
261.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gt_mcr.c
262   :doc: GT Multicast/Replicated (MCR) Register Support
263
264.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gt_mcr.c
265   :internal:
266
267Memory Management and Command Submission
268========================================
269
270This sections covers all things related to the GEM implementation in the
271i915 driver.
272
273Intel GPU Basics
274----------------
275
276An Intel GPU has multiple engines. There are several engine types:
277
278- Render Command Streamer (RCS). An engine for rendering 3D and
279  performing compute.
280- Blitting Command Streamer (BCS). An engine for performing blitting and/or
281  copying operations.
282- Video Command Streamer. An engine used for video encoding and decoding. Also
283  sometimes called 'BSD' in hardware documentation.
284- Video Enhancement Command Streamer (VECS). An engine for video enhancement.
285  Also sometimes called 'VEBOX' in hardware documentation.
286- Compute Command Streamer (CCS). An engine that has access to the media and
287  GPGPU pipelines, but not the 3D pipeline.
288- Graphics Security Controller (GSCCS). A dedicated engine for internal
289  communication with GSC controller on security related tasks like
290  High-bandwidth Digital Content Protection (HDCP), Protected Xe Path (PXP),
291  and HuC firmware authentication.
292
293The Intel GPU family is a family of integrated GPU's using Unified
294Memory Access. For having the GPU "do work", user space will feed the
295GPU batch buffers via one of the ioctls `DRM_IOCTL_I915_GEM_EXECBUFFER2`
296or `DRM_IOCTL_I915_GEM_EXECBUFFER2_WR`. Most such batchbuffers will
297instruct the GPU to perform work (for example rendering) and that work
298needs memory from which to read and memory to which to write. All memory
299is encapsulated within GEM buffer objects (usually created with the ioctl
300`DRM_IOCTL_I915_GEM_CREATE`). An ioctl providing a batchbuffer for the GPU
301to create will also list all GEM buffer objects that the batchbuffer reads
302and/or writes. For implementation details of memory management see
303`GEM BO Management Implementation Details`_.
304
305The i915 driver allows user space to create a context via the ioctl
306`DRM_IOCTL_I915_GEM_CONTEXT_CREATE` which is identified by a 32-bit
307integer. Such a context should be viewed by user-space as -loosely-
308analogous to the idea of a CPU process of an operating system. The i915
309driver guarantees that commands issued to a fixed context are to be
310executed so that writes of a previously issued command are seen by
311reads of following commands. Actions issued between different contexts
312(even if from the same file descriptor) are NOT given that guarantee
313and the only way to synchronize across contexts (even from the same
314file descriptor) is through the use of fences. At least as far back as
315Gen4, also have that a context carries with it a GPU HW context;
316the HW context is essentially (most of at least) the state of a GPU.
317In addition to the ordering guarantees, the kernel will restore GPU
318state via HW context when commands are issued to a context, this saves
319user space the need to restore (most of at least) the GPU state at the
320start of each batchbuffer. The non-deprecated ioctls to submit batchbuffer
321work can pass that ID (in the lower bits of drm_i915_gem_execbuffer2::rsvd1)
322to identify what context to use with the command.
323
324The GPU has its own memory management and address space. The kernel
325driver maintains the memory translation table for the GPU. For older
326GPUs (i.e. those before Gen8), there is a single global such translation
327table, a global Graphics Translation Table (GTT). For newer generation
328GPUs each context has its own translation table, called Per-Process
329Graphics Translation Table (PPGTT). Of important note, is that although
330PPGTT is named per-process it is actually per context. When user space
331submits a batchbuffer, the kernel walks the list of GEM buffer objects
332used by the batchbuffer and guarantees that not only is the memory of
333each such GEM buffer object resident but it is also present in the
334(PP)GTT. If the GEM buffer object is not yet placed in the (PP)GTT,
335then it is given an address. Two consequences of this are: the kernel
336needs to edit the batchbuffer submitted to write the correct value of
337the GPU address when a GEM BO is assigned a GPU address and the kernel
338might evict a different GEM BO from the (PP)GTT to make address room
339for another GEM BO. Consequently, the ioctls submitting a batchbuffer
340for execution also include a list of all locations within buffers that
341refer to GPU-addresses so that the kernel can edit the buffer correctly.
342This process is dubbed relocation.
343
344Locking Guidelines
345------------------
346
347.. note::
348   This is a description of how the locking should be after
349   refactoring is done. Does not necessarily reflect what the locking
350   looks like while WIP.
351
352#. All locking rules and interface contracts with cross-driver interfaces
353   (dma-buf, dma_fence) need to be followed.
354
355#. No struct_mutex anywhere in the code
356
357#. dma_resv will be the outermost lock (when needed) and ww_acquire_ctx
358   is to be hoisted at highest level and passed down within i915_gem_ctx
359   in the call chain
360
361#. While holding lru/memory manager (buddy, drm_mm, whatever) locks
362   system memory allocations are not allowed
363
364	* Enforce this by priming lockdep (with fs_reclaim). If we
365	  allocate memory while holding these looks we get a rehash
366	  of the shrinker vs. struct_mutex saga, and that would be
367	  real bad.
368
369#. Do not nest different lru/memory manager locks within each other.
370   Take them in turn to update memory allocations, relying on the object’s
371   dma_resv ww_mutex to serialize against other operations.
372
373#. The suggestion for lru/memory managers locks is that they are small
374   enough to be spinlocks.
375
376#. All features need to come with exhaustive kernel selftests and/or
377   IGT tests when appropriate
378
379#. All LMEM uAPI paths need to be fully restartable (_interruptible()
380   for all locks/waits/sleeps)
381
382	* Error handling validation through signal injection.
383	  Still the best strategy we have for validating GEM uAPI
384          corner cases.
385	  Must be excessively used in the IGT, and we need to check
386	  that we really have full path coverage of all error cases.
387
388	* -EDEADLK handling with ww_mutex
389
390GEM BO Management Implementation Details
391----------------------------------------
392
393.. kernel-doc:: drivers/gpu/drm/i915/i915_vma_types.h
394   :doc: Virtual Memory Address
395
396Buffer Object Eviction
397----------------------
398
399This section documents the interface functions for evicting buffer
400objects to make space available in the virtual gpu address spaces. Note
401that this is mostly orthogonal to shrinking buffer objects caches, which
402has the goal to make main memory (shared with the gpu through the
403unified memory architecture) available.
404
405.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_evict.c
406   :internal:
407
408Buffer Object Memory Shrinking
409------------------------------
410
411This section documents the interface function for shrinking memory usage
412of buffer object caches. Shrinking is used to make main memory
413available. Note that this is mostly orthogonal to evicting buffer
414objects, which has the goal to make space in gpu virtual address spaces.
415
416.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
417   :internal:
418
419Batchbuffer Parsing
420-------------------
421
422.. kernel-doc:: drivers/gpu/drm/i915/i915_cmd_parser.c
423   :doc: batch buffer command parser
424
425.. kernel-doc:: drivers/gpu/drm/i915/i915_cmd_parser.c
426   :internal:
427
428User Batchbuffer Execution
429--------------------------
430
431.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_context_types.h
432
433.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
434   :doc: User command execution
435
436Scheduling
437----------
438.. kernel-doc:: drivers/gpu/drm/i915/i915_scheduler_types.h
439   :functions: i915_sched_engine
440
441Logical Rings, Logical Ring Contexts and Execlists
442--------------------------------------------------
443
444.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_execlists_submission.c
445   :doc: Logical Rings, Logical Ring Contexts and Execlists
446
447Global GTT views
448----------------
449
450.. kernel-doc:: drivers/gpu/drm/i915/i915_vma_types.h
451   :doc: Global GTT views
452
453.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_gtt.c
454   :internal:
455
456GTT Fences and Swizzling
457------------------------
458
459.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
460   :internal:
461
462Global GTT Fence Handling
463~~~~~~~~~~~~~~~~~~~~~~~~~
464
465.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
466   :doc: fence register handling
467
468Hardware Tiling and Swizzling Details
469~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
470
471.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
472   :doc: tiling swizzling details
473
474Object Tiling IOCTLs
475--------------------
476
477.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_tiling.c
478   :internal:
479
480.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_tiling.c
481   :doc: buffer object tiling
482
483Protected Objects
484-----------------
485
486.. kernel-doc:: drivers/gpu/drm/i915/pxp/intel_pxp.c
487   :doc: PXP
488
489.. kernel-doc:: drivers/gpu/drm/i915/pxp/intel_pxp_types.h
490
491Microcontrollers
492================
493
494Starting from gen9, three microcontrollers are available on the HW: the
495graphics microcontroller (GuC), the HEVC/H.265 microcontroller (HuC) and the
496display microcontroller (DMC). The driver is responsible for loading the
497firmwares on the microcontrollers; the GuC and HuC firmwares are transferred
498to WOPCM using the DMA engine, while the DMC firmware is written through MMIO.
499
500WOPCM
501-----
502
503WOPCM Layout
504~~~~~~~~~~~~
505
506.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_wopcm.c
507   :doc: WOPCM Layout
508
509GuC
510---
511
512.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
513   :doc: GuC
514
515.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.h
516
517GuC Firmware Layout
518~~~~~~~~~~~~~~~~~~~
519
520.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_uc_fw_abi.h
521   :doc: Firmware Layout
522
523GuC Memory Management
524~~~~~~~~~~~~~~~~~~~~~
525
526.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
527   :doc: GuC Memory Management
528.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
529   :functions: intel_guc_allocate_vma
530
531
532GuC-specific firmware loader
533~~~~~~~~~~~~~~~~~~~~~~~~~~~~
534
535.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
536   :internal:
537
538GuC-based command submission
539~~~~~~~~~~~~~~~~~~~~~~~~~~~~
540
541.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
542   :doc: GuC-based command submission
543
544GuC ABI
545~~~~~~~~~~~~~~~~~~~~~~~~~~~~
546
547.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_messages_abi.h
548.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_communication_mmio_abi.h
549.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
550.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
551.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
552
553HuC
554---
555.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
556   :doc: HuC
557.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
558   :functions: intel_huc_auth
559
560HuC Memory Management
561~~~~~~~~~~~~~~~~~~~~~
562
563.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
564   :doc: HuC Memory Management
565
566HuC Firmware Layout
567~~~~~~~~~~~~~~~~~~~
568The HuC FW layout is the same as the GuC one, see `GuC Firmware Layout`_
569
570DMC
571---
572See `DMC Firmware Support`_
573
574Tracing
575=======
576
577This sections covers all things related to the tracepoints implemented
578in the i915 driver.
579
580i915_ppgtt_create and i915_ppgtt_release
581----------------------------------------
582
583.. kernel-doc:: drivers/gpu/drm/i915/i915_trace.h
584   :doc: i915_ppgtt_create and i915_ppgtt_release tracepoints
585
586i915_context_create and i915_context_free
587-----------------------------------------
588
589.. kernel-doc:: drivers/gpu/drm/i915/i915_trace.h
590   :doc: i915_context_create and i915_context_free tracepoints
591
592Perf
593====
594
595Overview
596--------
597.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
598   :doc: i915 Perf Overview
599
600Comparison with Core Perf
601-------------------------
602.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
603   :doc: i915 Perf History and Comparison with Core Perf
604
605i915 Driver Entry Points
606------------------------
607
608This section covers the entrypoints exported outside of i915_perf.c to
609integrate with drm/i915 and to handle the `DRM_I915_PERF_OPEN` ioctl.
610
611.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
612   :functions: i915_perf_init
613.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
614   :functions: i915_perf_fini
615.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
616   :functions: i915_perf_register
617.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
618   :functions: i915_perf_unregister
619.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
620   :functions: i915_perf_open_ioctl
621.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
622   :functions: i915_perf_release
623.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
624   :functions: i915_perf_add_config_ioctl
625.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
626   :functions: i915_perf_remove_config_ioctl
627
628i915 Perf Stream
629----------------
630
631This section covers the stream-semantics-agnostic structures and functions
632for representing an i915 perf stream FD and associated file operations.
633
634.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
635   :functions: i915_perf_stream
636.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
637   :functions: i915_perf_stream_ops
638
639.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
640   :functions: read_properties_unlocked
641.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
642   :functions: i915_perf_open_ioctl_locked
643.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
644   :functions: i915_perf_destroy_locked
645.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
646   :functions: i915_perf_read
647.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
648   :functions: i915_perf_ioctl
649.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
650   :functions: i915_perf_enable_locked
651.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
652   :functions: i915_perf_disable_locked
653.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
654   :functions: i915_perf_poll
655.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
656   :functions: i915_perf_poll_locked
657
658i915 Perf Observation Architecture Stream
659-----------------------------------------
660
661.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
662   :functions: i915_oa_ops
663
664.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
665   :functions: i915_oa_stream_init
666.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
667   :functions: i915_oa_read
668.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
669   :functions: i915_oa_stream_enable
670.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
671   :functions: i915_oa_stream_disable
672.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
673   :functions: i915_oa_wait_unlocked
674.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
675   :functions: i915_oa_poll_wait
676
677Other i915 Perf Internals
678-------------------------
679
680This section simply includes all other currently documented i915 perf internals,
681in no particular order, but may include some more minor utilities or platform
682specific details than found in the more high-level sections.
683
684.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
685   :internal:
686   :no-identifiers:
687       i915_perf_init
688       i915_perf_fini
689       i915_perf_register
690       i915_perf_unregister
691       i915_perf_open_ioctl
692       i915_perf_release
693       i915_perf_add_config_ioctl
694       i915_perf_remove_config_ioctl
695       read_properties_unlocked
696       i915_perf_open_ioctl_locked
697       i915_perf_destroy_locked
698       i915_perf_read i915_perf_ioctl
699       i915_perf_enable_locked
700       i915_perf_disable_locked
701       i915_perf_poll i915_perf_poll_locked
702       i915_oa_stream_init i915_oa_read
703       i915_oa_stream_enable
704       i915_oa_stream_disable
705       i915_oa_wait_unlocked
706       i915_oa_poll_wait
707
708Style
709=====
710
711The drm/i915 driver codebase has some style rules in addition to (and, in some
712cases, deviating from) the kernel coding style.
713
714Register macro definition style
715-------------------------------
716
717The style guide for ``i915_reg.h``.
718
719.. kernel-doc:: drivers/gpu/drm/i915/i915_reg.h
720   :doc: The i915 register macro definition style guide
721
722.. _i915-usage-stats:
723
724i915 DRM client usage stats implementation
725==========================================
726
727The drm/i915 driver implements the DRM client usage stats specification as
728documented in :ref:`drm-client-usage-stats`.
729
730Example of the output showing the implemented key value pairs and entirety of
731the currently possible format options:
732
733::
734
735      pos:    0
736      flags:  0100002
737      mnt_id: 21
738      drm-driver: i915
739      drm-pdev:   0000:00:02.0
740      drm-client-id:      7
741      drm-engine-render:  9288864723 ns
742      drm-engine-copy:    2035071108 ns
743      drm-engine-video:   0 ns
744      drm-engine-capacity-video:   2
745      drm-engine-video-enhance:   0 ns
746
747Possible `drm-engine-` key names are: `render`, `copy`, `video` and
748`video-enhance`.
749