xref: /linux/Documentation/gpu/i915.rst (revision 260f6f4fda93c8485c8037865c941b42b9cba5d2)
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_irq_suspend
39
40.. kernel-doc:: drivers/gpu/drm/i915/i915_irq.c
41   :functions: intel_irq_resume
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_plane.c
116   :doc: atomic plane helpers
117
118.. kernel-doc:: drivers/gpu/drm/i915/display/intel_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 Flip Queue
208--------------------
209
210.. kernel-doc:: drivers/gpu/drm/i915/display/intel_flipq.c
211   :doc: DMC Flip Queue
212
213DMC wakelock support
214--------------------
215
216.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc_wl.c
217   :doc: DMC wakelock support
218
219Video BIOS Table (VBT)
220----------------------
221
222.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c
223   :doc: Video BIOS Table (VBT)
224
225.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c
226   :internal:
227
228.. kernel-doc:: drivers/gpu/drm/i915/display/intel_vbt_defs.h
229   :internal:
230
231Display clocks
232--------------
233
234.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c
235   :doc: CDCLK / RAWCLK
236
237.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c
238   :internal:
239
240Display PLLs
241------------
242
243.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c
244   :doc: Display PLLs
245
246.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c
247   :internal:
248
249.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.h
250   :internal:
251
252Display State Buffer
253--------------------
254
255.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c
256   :doc: DSB
257
258.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c
259   :internal:
260
261GT Programming
262==============
263
264Multicast/Replicated (MCR) Registers
265------------------------------------
266
267.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gt_mcr.c
268   :doc: GT Multicast/Replicated (MCR) Register Support
269
270.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gt_mcr.c
271   :internal:
272
273Memory Management and Command Submission
274========================================
275
276This sections covers all things related to the GEM implementation in the
277i915 driver.
278
279Intel GPU Basics
280----------------
281
282An Intel GPU has multiple engines. There are several engine types:
283
284- Render Command Streamer (RCS). An engine for rendering 3D and
285  performing compute.
286- Blitting Command Streamer (BCS). An engine for performing blitting and/or
287  copying operations.
288- Video Command Streamer. An engine used for video encoding and decoding. Also
289  sometimes called 'BSD' in hardware documentation.
290- Video Enhancement Command Streamer (VECS). An engine for video enhancement.
291  Also sometimes called 'VEBOX' in hardware documentation.
292- Compute Command Streamer (CCS). An engine that has access to the media and
293  GPGPU pipelines, but not the 3D pipeline.
294- Graphics Security Controller (GSCCS). A dedicated engine for internal
295  communication with GSC controller on security related tasks like
296  High-bandwidth Digital Content Protection (HDCP), Protected Xe Path (PXP),
297  and HuC firmware authentication.
298
299The Intel GPU family is a family of integrated GPU's using Unified
300Memory Access. For having the GPU "do work", user space will feed the
301GPU batch buffers via one of the ioctls `DRM_IOCTL_I915_GEM_EXECBUFFER2`
302or `DRM_IOCTL_I915_GEM_EXECBUFFER2_WR`. Most such batchbuffers will
303instruct the GPU to perform work (for example rendering) and that work
304needs memory from which to read and memory to which to write. All memory
305is encapsulated within GEM buffer objects (usually created with the ioctl
306`DRM_IOCTL_I915_GEM_CREATE`). An ioctl providing a batchbuffer for the GPU
307to create will also list all GEM buffer objects that the batchbuffer reads
308and/or writes. For implementation details of memory management see
309`GEM BO Management Implementation Details`_.
310
311The i915 driver allows user space to create a context via the ioctl
312`DRM_IOCTL_I915_GEM_CONTEXT_CREATE` which is identified by a 32-bit
313integer. Such a context should be viewed by user-space as -loosely-
314analogous to the idea of a CPU process of an operating system. The i915
315driver guarantees that commands issued to a fixed context are to be
316executed so that writes of a previously issued command are seen by
317reads of following commands. Actions issued between different contexts
318(even if from the same file descriptor) are NOT given that guarantee
319and the only way to synchronize across contexts (even from the same
320file descriptor) is through the use of fences. At least as far back as
321Gen4, also have that a context carries with it a GPU HW context;
322the HW context is essentially (most of at least) the state of a GPU.
323In addition to the ordering guarantees, the kernel will restore GPU
324state via HW context when commands are issued to a context, this saves
325user space the need to restore (most of at least) the GPU state at the
326start of each batchbuffer. The non-deprecated ioctls to submit batchbuffer
327work can pass that ID (in the lower bits of drm_i915_gem_execbuffer2::rsvd1)
328to identify what context to use with the command.
329
330The GPU has its own memory management and address space. The kernel
331driver maintains the memory translation table for the GPU. For older
332GPUs (i.e. those before Gen8), there is a single global such translation
333table, a global Graphics Translation Table (GTT). For newer generation
334GPUs each context has its own translation table, called Per-Process
335Graphics Translation Table (PPGTT). Of important note, is that although
336PPGTT is named per-process it is actually per context. When user space
337submits a batchbuffer, the kernel walks the list of GEM buffer objects
338used by the batchbuffer and guarantees that not only is the memory of
339each such GEM buffer object resident but it is also present in the
340(PP)GTT. If the GEM buffer object is not yet placed in the (PP)GTT,
341then it is given an address. Two consequences of this are: the kernel
342needs to edit the batchbuffer submitted to write the correct value of
343the GPU address when a GEM BO is assigned a GPU address and the kernel
344might evict a different GEM BO from the (PP)GTT to make address room
345for another GEM BO. Consequently, the ioctls submitting a batchbuffer
346for execution also include a list of all locations within buffers that
347refer to GPU-addresses so that the kernel can edit the buffer correctly.
348This process is dubbed relocation.
349
350Locking Guidelines
351------------------
352
353.. note::
354   This is a description of how the locking should be after
355   refactoring is done. Does not necessarily reflect what the locking
356   looks like while WIP.
357
358#. All locking rules and interface contracts with cross-driver interfaces
359   (dma-buf, dma_fence) need to be followed.
360
361#. No struct_mutex anywhere in the code
362
363#. dma_resv will be the outermost lock (when needed) and ww_acquire_ctx
364   is to be hoisted at highest level and passed down within i915_gem_ctx
365   in the call chain
366
367#. While holding lru/memory manager (buddy, drm_mm, whatever) locks
368   system memory allocations are not allowed
369
370	* Enforce this by priming lockdep (with fs_reclaim). If we
371	  allocate memory while holding these looks we get a rehash
372	  of the shrinker vs. struct_mutex saga, and that would be
373	  real bad.
374
375#. Do not nest different lru/memory manager locks within each other.
376   Take them in turn to update memory allocations, relying on the object’s
377   dma_resv ww_mutex to serialize against other operations.
378
379#. The suggestion for lru/memory managers locks is that they are small
380   enough to be spinlocks.
381
382#. All features need to come with exhaustive kernel selftests and/or
383   IGT tests when appropriate
384
385#. All LMEM uAPI paths need to be fully restartable (_interruptible()
386   for all locks/waits/sleeps)
387
388	* Error handling validation through signal injection.
389	  Still the best strategy we have for validating GEM uAPI
390          corner cases.
391	  Must be excessively used in the IGT, and we need to check
392	  that we really have full path coverage of all error cases.
393
394	* -EDEADLK handling with ww_mutex
395
396GEM BO Management Implementation Details
397----------------------------------------
398
399.. kernel-doc:: drivers/gpu/drm/i915/i915_vma_types.h
400   :doc: Virtual Memory Address
401
402Buffer Object Eviction
403----------------------
404
405This section documents the interface functions for evicting buffer
406objects to make space available in the virtual gpu address spaces. Note
407that this is mostly orthogonal to shrinking buffer objects caches, which
408has the goal to make main memory (shared with the gpu through the
409unified memory architecture) available.
410
411.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_evict.c
412   :internal:
413
414Buffer Object Memory Shrinking
415------------------------------
416
417This section documents the interface function for shrinking memory usage
418of buffer object caches. Shrinking is used to make main memory
419available. Note that this is mostly orthogonal to evicting buffer
420objects, which has the goal to make space in gpu virtual address spaces.
421
422.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
423   :internal:
424
425Batchbuffer Parsing
426-------------------
427
428.. kernel-doc:: drivers/gpu/drm/i915/i915_cmd_parser.c
429   :doc: batch buffer command parser
430
431.. kernel-doc:: drivers/gpu/drm/i915/i915_cmd_parser.c
432   :internal:
433
434User Batchbuffer Execution
435--------------------------
436
437.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_context_types.h
438
439.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
440   :doc: User command execution
441
442Scheduling
443----------
444.. kernel-doc:: drivers/gpu/drm/i915/i915_scheduler_types.h
445   :functions: i915_sched_engine
446
447Logical Rings, Logical Ring Contexts and Execlists
448--------------------------------------------------
449
450.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_execlists_submission.c
451   :doc: Logical Rings, Logical Ring Contexts and Execlists
452
453Global GTT views
454----------------
455
456.. kernel-doc:: drivers/gpu/drm/i915/i915_vma_types.h
457   :doc: Global GTT views
458
459.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_gtt.c
460   :internal:
461
462GTT Fences and Swizzling
463------------------------
464
465.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
466   :internal:
467
468Global GTT Fence Handling
469~~~~~~~~~~~~~~~~~~~~~~~~~
470
471.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
472   :doc: fence register handling
473
474Hardware Tiling and Swizzling Details
475~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
476
477.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
478   :doc: tiling swizzling details
479
480Object Tiling IOCTLs
481--------------------
482
483.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_tiling.c
484   :internal:
485
486.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_tiling.c
487   :doc: buffer object tiling
488
489Protected Objects
490-----------------
491
492.. kernel-doc:: drivers/gpu/drm/i915/pxp/intel_pxp.c
493   :doc: PXP
494
495.. kernel-doc:: drivers/gpu/drm/i915/pxp/intel_pxp_types.h
496
497Microcontrollers
498================
499
500Starting from gen9, three microcontrollers are available on the HW: the
501graphics microcontroller (GuC), the HEVC/H.265 microcontroller (HuC) and the
502display microcontroller (DMC). The driver is responsible for loading the
503firmwares on the microcontrollers; the GuC and HuC firmwares are transferred
504to WOPCM using the DMA engine, while the DMC firmware is written through MMIO.
505
506WOPCM
507-----
508
509WOPCM Layout
510~~~~~~~~~~~~
511
512.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_wopcm.c
513   :doc: WOPCM Layout
514
515GuC
516---
517
518.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
519   :doc: GuC
520
521.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.h
522
523GuC Firmware Layout
524~~~~~~~~~~~~~~~~~~~
525
526.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_uc_fw_abi.h
527   :doc: Firmware Layout
528
529GuC Memory Management
530~~~~~~~~~~~~~~~~~~~~~
531
532.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
533   :doc: GuC Memory Management
534.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc.c
535   :functions: intel_guc_allocate_vma
536
537
538GuC-specific firmware loader
539~~~~~~~~~~~~~~~~~~~~~~~~~~~~
540
541.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
542   :internal:
543
544GuC-based command submission
545~~~~~~~~~~~~~~~~~~~~~~~~~~~~
546
547.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
548   :doc: GuC-based command submission
549
550GuC ABI
551~~~~~~~~~~~~~~~~~~~~~~~~~~~~
552
553.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_messages_abi.h
554.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_communication_mmio_abi.h
555.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
556.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
557.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
558
559HuC
560---
561.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
562   :doc: HuC
563.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
564   :functions: intel_huc_auth
565
566HuC Memory Management
567~~~~~~~~~~~~~~~~~~~~~
568
569.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c
570   :doc: HuC Memory Management
571
572HuC Firmware Layout
573~~~~~~~~~~~~~~~~~~~
574The HuC FW layout is the same as the GuC one, see `GuC Firmware Layout`_
575
576DMC
577---
578See `DMC Firmware Support`_
579
580Tracing
581=======
582
583This sections covers all things related to the tracepoints implemented
584in the i915 driver.
585
586i915_ppgtt_create and i915_ppgtt_release
587----------------------------------------
588
589.. kernel-doc:: drivers/gpu/drm/i915/i915_trace.h
590   :doc: i915_ppgtt_create and i915_ppgtt_release tracepoints
591
592i915_context_create and i915_context_free
593-----------------------------------------
594
595.. kernel-doc:: drivers/gpu/drm/i915/i915_trace.h
596   :doc: i915_context_create and i915_context_free tracepoints
597
598Perf
599====
600
601Overview
602--------
603.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
604   :doc: i915 Perf Overview
605
606Comparison with Core Perf
607-------------------------
608.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
609   :doc: i915 Perf History and Comparison with Core Perf
610
611i915 Driver Entry Points
612------------------------
613
614This section covers the entrypoints exported outside of i915_perf.c to
615integrate with drm/i915 and to handle the `DRM_I915_PERF_OPEN` ioctl.
616
617.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
618   :functions: i915_perf_init
619.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
620   :functions: i915_perf_fini
621.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
622   :functions: i915_perf_register
623.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
624   :functions: i915_perf_unregister
625.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
626   :functions: i915_perf_open_ioctl
627.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
628   :functions: i915_perf_release
629.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
630   :functions: i915_perf_add_config_ioctl
631.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
632   :functions: i915_perf_remove_config_ioctl
633
634i915 Perf Stream
635----------------
636
637This section covers the stream-semantics-agnostic structures and functions
638for representing an i915 perf stream FD and associated file operations.
639
640.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
641   :functions: i915_perf_stream
642.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
643   :functions: i915_perf_stream_ops
644
645.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
646   :functions: read_properties_unlocked
647.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
648   :functions: i915_perf_open_ioctl_locked
649.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
650   :functions: i915_perf_destroy_locked
651.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
652   :functions: i915_perf_read
653.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
654   :functions: i915_perf_ioctl
655.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
656   :functions: i915_perf_enable_locked
657.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
658   :functions: i915_perf_disable_locked
659.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
660   :functions: i915_perf_poll
661.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
662   :functions: i915_perf_poll_locked
663
664i915 Perf Observation Architecture Stream
665-----------------------------------------
666
667.. kernel-doc:: drivers/gpu/drm/i915/i915_perf_types.h
668   :functions: i915_oa_ops
669
670.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
671   :functions: i915_oa_stream_init
672.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
673   :functions: i915_oa_read
674.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
675   :functions: i915_oa_stream_enable
676.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
677   :functions: i915_oa_stream_disable
678.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
679   :functions: i915_oa_wait_unlocked
680.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
681   :functions: i915_oa_poll_wait
682
683Other i915 Perf Internals
684-------------------------
685
686This section simply includes all other currently documented i915 perf internals,
687in no particular order, but may include some more minor utilities or platform
688specific details than found in the more high-level sections.
689
690.. kernel-doc:: drivers/gpu/drm/i915/i915_perf.c
691   :internal:
692   :no-identifiers:
693       i915_perf_init
694       i915_perf_fini
695       i915_perf_register
696       i915_perf_unregister
697       i915_perf_open_ioctl
698       i915_perf_release
699       i915_perf_add_config_ioctl
700       i915_perf_remove_config_ioctl
701       read_properties_unlocked
702       i915_perf_open_ioctl_locked
703       i915_perf_destroy_locked
704       i915_perf_read i915_perf_ioctl
705       i915_perf_enable_locked
706       i915_perf_disable_locked
707       i915_perf_poll i915_perf_poll_locked
708       i915_oa_stream_init i915_oa_read
709       i915_oa_stream_enable
710       i915_oa_stream_disable
711       i915_oa_wait_unlocked
712       i915_oa_poll_wait
713
714Style
715=====
716
717The drm/i915 driver codebase has some style rules in addition to (and, in some
718cases, deviating from) the kernel coding style.
719
720Register macro definition style
721-------------------------------
722
723The style guide for ``i915_reg.h``.
724
725.. kernel-doc:: drivers/gpu/drm/i915/i915_reg.h
726   :doc: The i915 register macro definition style guide
727
728.. _i915-usage-stats:
729
730i915 DRM client usage stats implementation
731==========================================
732
733The drm/i915 driver implements the DRM client usage stats specification as
734documented in :ref:`drm-client-usage-stats`.
735
736Example of the output showing the implemented key value pairs and entirety of
737the currently possible format options:
738
739::
740
741      pos:    0
742      flags:  0100002
743      mnt_id: 21
744      drm-driver: i915
745      drm-pdev:   0000:00:02.0
746      drm-client-id:      7
747      drm-engine-render:  9288864723 ns
748      drm-engine-copy:    2035071108 ns
749      drm-engine-video:   0 ns
750      drm-engine-capacity-video:   2
751      drm-engine-video-enhance:   0 ns
752
753Possible `drm-engine-` key names are: `render`, `copy`, `video` and
754`video-enhance`.
755