diff options
author | Dave Airlie <airlied@redhat.com> | 2021-06-02 14:04:29 +1000 |
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committer | Dave Airlie <airlied@redhat.com> | 2021-06-02 14:15:54 +1000 |
commit | ccd1950c2f7e38ae45aeefb99a08b39407cd6c63 (patch) | |
tree | 1fe82742fce2934ec5720e7bc265dabc8c015656 /Documentation/gpu | |
parent | 43ed3c6c786d996a264fcde68dbb36df6f03b965 (diff) | |
parent | 5b26d57fdb499c2363f3d895ef008e73ec02eb9b (diff) |
Merge tag 'drm-intel-gt-next-2021-05-28' of git://anongit.freedesktop.org/drm/drm-intel into drm-next
UAPI Changes:
- Add reworked uAPI for DG1 behind CONFIG_BROKEN (Matt A, Abdiel)
Driver Changes:
- Fix for Gitlab issues #3293 and #3450:
Avoid kernel crash on older L-shape memory machines
- Add Wa_14010733141 (VDBox SFC reset) for Gen11+ (Aditya)
- Fix crash in auto_retire active retire callback due to
misalignment (Stephane)
- Fix overlay active retire callback alignment (Tvrtko)
- Eliminate need to align active retire callbacks (Matt A, Ville,
Daniel)
- Program FF_MODE2 tuning value for all Gen12 platforms (Caz)
- Add Wa_14011060649 for TGL,RKL,DG1 and ADLS (Swathi)
- Create stolen memory region from local memory on DG1 (CQ)
- Place PD in LMEM on dGFX (Matt A)
- Use WC when default state object is allocated in LMEM (Venkata)
- Determine the coherent map type based on object location (Venkata)
- Use lmem physical addresses for fb_mmap() on discrete (Mohammed)
- Bypass aperture on fbdev when LMEM is available (Anusha)
- Return error value when displayable BO not in LMEM for dGFX (Mohammed)
- Do release kernel context if breadcrumb measure fails (Janusz)
- Hide modparams for compiled-out features (Tvrtko)
- Apply Wa_22010271021 for all Gen11 platforms (Caz)
- Fix unlikely ref count race in arming the watchdog timer (Tvrtko)
- Check actual RC6 enable status in PMU (Tvrtko)
- Fix a double free in gen8_preallocate_top_level_pdp (Lv)
- Use trylock in shrinker for GGTT on BSW VT-d and BXT (Maarten)
- Remove erroneous i915_is_ggtt check for
I915_GEM_OBJECT_UNBIND_VM_TRYLOCK (Maarten)
- Convert uAPI headers to real kerneldoc (Matt A)
- Clean up kerneldoc warnings headers (Matt A, Maarten)
- Fail driver if LMEM training failed (Matt R)
- Avoid div-by-zero on Gen2 (Ville)
- Read C0DRB3/C1DRB3 as 16 bits again and add _BW suffix (Ville)
- Remove reference to struct drm_device.pdev (Thomas)
- Increase separation between GuC and execlists code (Chris, Matt B)
- Use might_alloc() (Bernard)
- Split DGFX_FEATURES from GEN12_FEATURES (Lucas)
- Deduplicate Wa_22010271021 programming on (Jose)
- Drop duplicate WaDisable4x2SubspanOptimization:hsw (Tvrtko)
- Selftest improvements (Chris, Hsin-Yi, Tvrtko)
- Shuffle around init_memory_region for stolen (Matt)
- Typo fixes (wengjianfeng)
[airlied: fix conflict with fixes in i915_active.c]
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YLCbBR22BsQ/dpJB@jlahtine-mobl.ger.corp.intel.com
Diffstat (limited to 'Documentation/gpu')
-rw-r--r-- | Documentation/gpu/driver-uapi.rst | 8 | ||||
-rw-r--r-- | Documentation/gpu/index.rst | 1 | ||||
-rw-r--r-- | Documentation/gpu/rfc/i915_gem_lmem.rst | 131 | ||||
-rw-r--r-- | Documentation/gpu/rfc/index.rst | 4 |
4 files changed, 144 insertions, 0 deletions
diff --git a/Documentation/gpu/driver-uapi.rst b/Documentation/gpu/driver-uapi.rst new file mode 100644 index 000000000000..4411e6919a3d --- /dev/null +++ b/Documentation/gpu/driver-uapi.rst @@ -0,0 +1,8 @@ +=============== +DRM Driver uAPI +=============== + +drm/i915 uAPI +============= + +.. kernel-doc:: include/uapi/drm/i915_drm.h diff --git a/Documentation/gpu/index.rst b/Documentation/gpu/index.rst index ec4bc72438e4..b9c1214d8f23 100644 --- a/Documentation/gpu/index.rst +++ b/Documentation/gpu/index.rst @@ -10,6 +10,7 @@ Linux GPU Driver Developer's Guide drm-kms drm-kms-helpers drm-uapi + driver-uapi drm-client drivers backlight diff --git a/Documentation/gpu/rfc/i915_gem_lmem.rst b/Documentation/gpu/rfc/i915_gem_lmem.rst new file mode 100644 index 000000000000..675ba8620d66 --- /dev/null +++ b/Documentation/gpu/rfc/i915_gem_lmem.rst @@ -0,0 +1,131 @@ +========================= +I915 DG1/LMEM RFC Section +========================= + +Upstream plan +============= +For upstream the overall plan for landing all the DG1 stuff and turning it for +real, with all the uAPI bits is: + +* Merge basic HW enabling of DG1(still without pciid) +* Merge the uAPI bits behind special CONFIG_BROKEN(or so) flag + * At this point we can still make changes, but importantly this lets us + start running IGTs which can utilize local-memory in CI +* Convert over to TTM, make sure it all keeps working. Some of the work items: + * TTM shrinker for discrete + * dma_resv_lockitem for full dma_resv_lock, i.e not just trylock + * Use TTM CPU pagefault handler + * 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 diff --git a/Documentation/gpu/rfc/index.rst b/Documentation/gpu/rfc/index.rst index a8621f7dab8b..05670442ca1b 100644 --- a/Documentation/gpu/rfc/index.rst +++ b/Documentation/gpu/rfc/index.rst @@ -15,3 +15,7 @@ host such documentation: * Once the code has landed move all the documentation to the right places in the main core, helper or driver sections. + +.. toctree:: + + i915_gem_lmem.rst |