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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-11-01 19:28:35 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-11-01 19:28:35 +0300 |
commit | 7d461b291e65938f15f56fe58da2303b07578a76 (patch) | |
tree | 015dd7c2f1743dd70be52787dd9aff33822bc938 /Documentation/driver-api | |
parent | 8bc9e6515183935fa0cccaf67455c439afe4982b (diff) | |
parent | 631808095a82e6b6f8410a95f8b12b8d0d38b161 (diff) | |
download | linux-7d461b291e65938f15f56fe58da2303b07578a76.tar.xz |
Merge tag 'drm-next-2023-10-31-1' of git://anongit.freedesktop.org/drm/drm
Pull drm updates from Dave Airlie:
"Highlights:
- AMD adds some more upcoming HW platforms
- Intel made Meteorlake stable and started adding Lunarlake
- nouveau has a bunch of display rework in prepartion for the NVIDIA
GSP firmware support
- msm adds a7xx support
- habanalabs has finished migration to accel subsystem
Detail summary:
kernel:
- add initial vmemdup-user-array
core:
- fix platform remove() to return void
- drm_file owner updated to reflect owner
- move size calcs to drm buddy allocator
- let GPUVM build as a module
- allow variable number of run-queues in scheduler
edid:
- handle bad h/v sync_end in EDIDs
panfrost:
- add Boris as maintainer
fbdev:
- use fb_ops helpers more
- only allow logo use from fbcon
- rename fb_pgproto to pgprot_framebuffer
- add HPD state to drm_connector_oob_hotplug_event
- convert to fbdev i/o mem helpers
i915:
- Enable meteorlake by default
- Early Xe2 LPD/Lunarlake display enablement
- Rework subplatforms into IP version checks
- GuC based TLB invalidation for Meteorlake
- Display rework for future Xe driver integration
- LNL FBC features
- LNL display feature capability reads
- update recommended fw versions for DG2+
- drop fastboot module parameter
- added deviceid for Arrowlake-S
- drop preproduction workarounds
- don't disable preemption for resets
- cleanup inlines in headers
- PXP firmware loading fix
- Fix sg list lengths
- DSC PPS state readout/verification
- Add more RPL P/U PCI IDs
- Add new DG2-G12 stepping
- DP enhanced framing support to state checker
- Improve shared link bandwidth management
- stop using GEM macros in display code
- refactor related code into display code
- locally enable W=1 warnings
- remove PSR watchdog timers on LNL
amdgpu:
- RAS/FRU EEPROM updatse
- IP discovery updatses
- GC 11.5 support
- DCN 3.5 support
- VPE 6.1 support
- NBIO 7.11 support
- DML2 support
- lots of IP updates
- use flexible arrays for bo list handling
- W=1 fixes
- Enable seamless boot in more cases
- Enable context type property for HDMI
- Rework GPUVM TLB flushing
- VCN IB start/size alignment fixes
amdkfd:
- GC 10/11 fixes
- GC 11.5 support
- use partial migration in GPU faults
radeon:
- W=1 Fixes
- fix some possible buffer overflow/NULL derefs
nouveau:
- update uapi for NO_PREFETCH
- scheduler/fence fixes
- rework suspend/resume for GSP-RM
- rework display in preparation for GSP-RM
habanalabs:
- uapi: expose tsc clock
- uapi: block access to eventfd through control device
- uapi: force dma-buf export to PAGE_SIZE alignments
- complete move to accel subsystem
- move firmware interface include files
- perform hard reset on PCIe AXI drain event
- optimise user interrupt handling
msm:
- DP: use existing helpers for DPCD
- DPU: interrupts reworked
- gpu: a7xx (a730/a740) support
- decouple msm_drv from kms for headless devices
mediatek:
- MT8188 dsi/dp/edp support
- DDP GAMMA - 12 bit LUT support
- connector dynamic selection capability
rockchip:
- rv1126 mipi-dsi/vop support
- add planar formats
ast:
- rename constants
panels:
- Mitsubishi AA084XE01
- JDI LPM102A188A
- LTK050H3148W-CTA6
ivpu:
- power management fixes
qaic:
- add detach slice bo api
komeda:
- add NV12 writeback
tegra:
- support NVSYNC/NHSYNC
- host1x suspend fixes
ili9882t:
- separate into own driver"
* tag 'drm-next-2023-10-31-1' of git://anongit.freedesktop.org/drm/drm: (1803 commits)
drm/amdgpu: Remove unused variables from amdgpu_show_fdinfo
drm/amdgpu: Remove duplicate fdinfo fields
drm/amd/amdgpu: avoid to disable gfxhub interrupt when driver is unloaded
drm/amdgpu: Add EXT_COHERENT support for APU and NUMA systems
drm/amdgpu: Retrieve CE count from ce_count_lo_chip in EccInfo table
drm/amdgpu: Identify data parity error corrected in replay mode
drm/amdgpu: Fix typo in IP discovery parsing
drm/amd/display: fix S/G display enablement
drm/amdxcp: fix amdxcp unloads incompletely
drm/amd/amdgpu: fix the GPU power print error in pm info
drm/amdgpu: Use pcie domain of xcc acpi objects
drm/amd: check num of link levels when update pcie param
drm/amdgpu: Add a read to GFX v9.4.3 ring test
drm/amd/pm: call smu_cmn_get_smc_version in is_mode1_reset_supported.
drm/amdgpu: get RAS poison status from DF v4_6_2
drm/amdgpu: Use discovery table's subrevision
drm/amd/display: 3.2.256
drm/amd/display: add interface to query SubVP status
drm/amd/display: Read before writing Backlight Mode Set Register
drm/amd/display: Disable SYMCLK32_SE RCO on DCN314
...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r-- | Documentation/driver-api/dma-buf.rst | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst index f92a32d095d9..0c153d79ccc4 100644 --- a/Documentation/driver-api/dma-buf.rst +++ b/Documentation/driver-api/dma-buf.rst @@ -5,14 +5,30 @@ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. -This is used, for example, by drm "prime" multi-GPU support, but is of -course not limited to GPU use cases. - -The three main components of this are: (1) dma-buf, representing a -sg_table and exposed to userspace as a file descriptor to allow passing -between devices, (2) fence, which provides a mechanism to signal when -one device has finished access, and (3) reservation, which manages the -shared or exclusive fence(s) associated with the buffer. +As an example, it is used extensively by the DRM subsystem to exchange +buffers between processes, contexts, library APIs within the same +process, and also to exchange buffers with other subsystems such as +V4L2. + +This document describes the way in which kernel subsystems can use and +interact with the three main primitives offered by dma-buf: + + - dma-buf, representing a sg_table and exposed to userspace as a file + descriptor to allow passing between processes, subsystems, devices, + etc; + - dma-fence, providing a mechanism to signal when an asynchronous + hardware operation has completed; and + - dma-resv, which manages a set of dma-fences for a particular dma-buf + allowing implicit (kernel-ordered) synchronization of work to + preserve the illusion of coherent access + + +Userspace API principles and use +-------------------------------- + +For more details on how to design your subsystem's API for dma-buf use, please +see Documentation/userspace-api/dma-buf-alloc-exchange.rst. + Shared DMA Buffers ------------------ |