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authorLinus Torvalds2021-08-12 16:09:25 -1000
committerLinus Torvalds2021-08-12 16:09:25 -1000
commit82cce5f4291e089d44b7b9bc77918cbcd52d429e (patch)
tree882542dc3f9ece7f5e825a109e7cde9a2e9fdb17 /Documentation
parentf8fbb47c6e86c0b75f8df864db702c3e3f757361 (diff)
parenta1fa72683166b3c69511d5f2ffb37b9f49f48fea (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.rst109
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