diff options
author | Linus Torvalds | 2021-08-12 16:09:25 -1000 |
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committer | Linus Torvalds | 2021-08-12 16:09:25 -1000 |
commit | 82cce5f4291e089d44b7b9bc77918cbcd52d429e (patch) | |
tree | 882542dc3f9ece7f5e825a109e7cde9a2e9fdb17 /Documentation | |
parent | f8fbb47c6e86c0b75f8df864db702c3e3f757361 (diff) | |
parent | a1fa72683166b3c69511d5f2ffb37b9f49f48fea (diff) |
Merge tag 'drm-fixes-2021-08-13' of git://anongit.freedesktop.org/drm/drm
Pull drm fixes from Dave Airlie:
"Another week, another set of pretty regular fixes, nothing really
stands out too much.
amdgpu:
- Yellow carp update
- RAS EEPROM fixes
- BACO/BOCO fixes
- Fix a memory leak in an error path
- Freesync fix
- VCN harvesting fix
- Display fixes
i915:
- GVT fix for Windows VM hang.
- Display fix of 12 BPC bits for display 12 and newer.
- Don't try to access some media register for fused off domains.
- Fix kerneldoc build warnings.
mediatek:
- Fix dpi bridge bug.
- Fix cursor plane no update.
meson:
- Fix colors when booting with HDR"
* tag 'drm-fixes-2021-08-13' of git://anongit.freedesktop.org/drm/drm:
drm/doc/rfc: drop lmem uapi section
drm/i915: Only access SFC_DONE when media domain is not fused off
drm/i915/display: Fix the 12 BPC bits for PIPE_MISC reg
drm/amd/display: use GFP_ATOMIC in amdgpu_dm_irq_schedule_work
drm/amd/display: Remove invalid assert for ODM + MPC case
drm/amd/pm: bug fix for the runtime pm BACO
drm/amdgpu: handle VCN instances when harvesting (v2)
drm/meson: fix colour distortion from HDR set during vendor u-boot
drm/i915/gvt: Fix cached atomics setting for Windows VM
drm/amdgpu: Add preferred mode in modeset when freesync video mode's enabled.
drm/amd/pm: Fix a memory leak in an error handling path in 'vangogh_tables_init()'
drm/amdgpu: don't enable baco on boco platforms in runpm
drm/amdgpu: set RAS EEPROM address from VBIOS
drm/amd/pm: update smu v13.0.1 firmware header
drm/mediatek: Fix cursor plane no update
drm/mediatek: mtk-dpi: Set out_fmt from config if not the last bridge
drm/mediatek: dpi: Fix NULL dereference in mtk_dpi_bridge_atomic_check
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/gpu/rfc/i915_gem_lmem.rst | 109 |
1 files changed, 0 insertions, 109 deletions
diff --git a/Documentation/gpu/rfc/i915_gem_lmem.rst b/Documentation/gpu/rfc/i915_gem_lmem.rst index 675ba8620d66..b421a3c1806e 100644 --- a/Documentation/gpu/rfc/i915_gem_lmem.rst +++ b/Documentation/gpu/rfc/i915_gem_lmem.rst @@ -18,114 +18,5 @@ real, with all the uAPI bits is: * Route shmem backend over to TTM SYSTEM for discrete * TTM purgeable object support * Move i915 buddy allocator over to TTM - * MMAP ioctl mode(see `I915 MMAP`_) - * SET/GET ioctl caching(see `I915 SET/GET CACHING`_) * Send RFC(with mesa-dev on cc) for final sign off on the uAPI * Add pciid for DG1 and turn on uAPI for real - -New object placement and region query uAPI -========================================== -Starting from DG1 we need to give userspace the ability to allocate buffers from -device local-memory. Currently the driver supports gem_create, which can place -buffers in system memory via shmem, and the usual assortment of other -interfaces, like dumb buffers and userptr. - -To support this new capability, while also providing a uAPI which will work -beyond just DG1, we propose to offer three new bits of uAPI: - -DRM_I915_QUERY_MEMORY_REGIONS ------------------------------ -New query ID which allows userspace to discover the list of supported memory -regions(like system-memory and local-memory) for a given device. We identify -each region with a class and instance pair, which should be unique. The class -here would be DEVICE or SYSTEM, and the instance would be zero, on platforms -like DG1. - -Side note: The class/instance design is borrowed from our existing engine uAPI, -where we describe every physical engine in terms of its class, and the -particular instance, since we can have more than one per class. - -In the future we also want to expose more information which can further -describe the capabilities of a region. - -.. kernel-doc:: include/uapi/drm/i915_drm.h - :functions: drm_i915_gem_memory_class drm_i915_gem_memory_class_instance drm_i915_memory_region_info drm_i915_query_memory_regions - -GEM_CREATE_EXT --------------- -New ioctl which is basically just gem_create but now allows userspace to provide -a chain of possible extensions. Note that if we don't provide any extensions and -set flags=0 then we get the exact same behaviour as gem_create. - -Side note: We also need to support PXP[1] in the near future, which is also -applicable to integrated platforms, and adds its own gem_create_ext extension, -which basically lets userspace mark a buffer as "protected". - -.. kernel-doc:: include/uapi/drm/i915_drm.h - :functions: drm_i915_gem_create_ext - -I915_GEM_CREATE_EXT_MEMORY_REGIONS ----------------------------------- -Implemented as an extension for gem_create_ext, we would now allow userspace to -optionally provide an immutable list of preferred placements at creation time, -in priority order, for a given buffer object. For the placements we expect -them each to use the class/instance encoding, as per the output of the regions -query. Having the list in priority order will be useful in the future when -placing an object, say during eviction. - -.. kernel-doc:: include/uapi/drm/i915_drm.h - :functions: drm_i915_gem_create_ext_memory_regions - -One fair criticism here is that this seems a little over-engineered[2]. If we -just consider DG1 then yes, a simple gem_create.flags or something is totally -all that's needed to tell the kernel to allocate the buffer in local-memory or -whatever. However looking to the future we need uAPI which can also support -upcoming Xe HP multi-tile architecture in a sane way, where there can be -multiple local-memory instances for a given device, and so using both class and -instance in our uAPI to describe regions is desirable, although specifically -for DG1 it's uninteresting, since we only have a single local-memory instance. - -Existing uAPI issues -==================== -Some potential issues we still need to resolve. - -I915 MMAP ---------- -In i915 there are multiple ways to MMAP GEM object, including mapping the same -object using different mapping types(WC vs WB), i.e multiple active mmaps per -object. TTM expects one MMAP at most for the lifetime of the object. If it -turns out that we have to backpedal here, there might be some potential -userspace fallout. - -I915 SET/GET CACHING --------------------- -In i915 we have set/get_caching ioctl. TTM doesn't let us to change this, but -DG1 doesn't support non-snooped pcie transactions, so we can just always -allocate as WB for smem-only buffers. If/when our hw gains support for -non-snooped pcie transactions then we must fix this mode at allocation time as -a new GEM extension. - -This is related to the mmap problem, because in general (meaning, when we're -not running on intel cpus) the cpu mmap must not, ever, be inconsistent with -allocation mode. - -Possible idea is to let the kernel picks the mmap mode for userspace from the -following table: - -smem-only: WB. Userspace does not need to call clflush. - -smem+lmem: We only ever allow a single mode, so simply allocate this as uncached -memory, and always give userspace a WC mapping. GPU still does snooped access -here(assuming we can't turn it off like on DG1), which is a bit inefficient. - -lmem only: always WC - -This means on discrete you only get a single mmap mode, all others must be -rejected. That's probably going to be a new default mode or something like -that. - -Links -===== -[1] https://patchwork.freedesktop.org/series/86798/ - -[2] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5599#note_553791 |