[PATCH v3 0/5] drm/i915: Allow user to set cache at BO creation

[Yang, Fei]

> On 4/28/23 07:47, fei.yang at intel.com wrote:
>> From: Fei Yang <fei.yang at intel.com>
>>
>> The first three patches in this series are taken from
>> https://patchwork.freedesktop.org/series/116868/
>> These patches are included here because the last patch
>> has dependency on the pat_index refactor.
>>
>> This series is focusing on uAPI changes,
>> 1. end support for set caching ioctl [PATCH 4/5]
>> 2. add set_pat extension for gem_create [PATCH 5/5]
>>
>> v2: drop one patch that was merged separately
>>      341ad0e8e254 drm/i915/mtl: Add PTE encode function
>> v3: rebase on https://patchwork.freedesktop.org/series/117082/
>
> Hi, Fei.
>
> Does this uAPI update also affect any discrete GPUs supported by i915,

It does.

> And in that case, does it allow setting non-snooping PAT indices on
> those devices?

It allows setting PAT indices specified in https://gfxspecs.intel.com/Predator/Home/Index/45101 .
KMD does a sanity check so that it won't go over the max recommended
by bspec.

> If so, since the uAPI for discrete GPU devices doesn't allow incoherency
> between GPU and CPU (apart from write-combining buffering), the correct
> CPU caching mode matching the PAT index needs to be selected for the
> buffer object in i915_ttm_select_tt_caching().

The patch doesn't affect the CPU caching mode setting logic though.
And the caching settings for objects created by kernel should remain
the same for both CPU and GPU, objects created by userspace are
managed completely by userspace.

One question though, what do you mean by non-snooping PAT indices?
The PAT index registers don't really control coherency mode in the past,
I believe MTL is the first one that has COH_MODE in the PAT registers.
Aren't discrete GPUs snooping CPU cache automatically?

-Fei

> Thanks,
> Thomas
>
>>
>> Fei Yang (5):
>>    drm/i915: preparation for using PAT index
>>    drm/i915: use pat_index instead of cache_level
>>    drm/i915: make sure correct pte encode is used
>>    drm/i915/mtl: end support for set caching ioctl
>>    drm/i915: Allow user to set cache at BO creation
>>
>>   drivers/gpu/drm/i915/display/intel_dpt.c      | 12 +--
>>   drivers/gpu/drm/i915/gem/i915_gem_create.c    | 36 +++++++++
>>   drivers/gpu/drm/i915/gem/i915_gem_domain.c    | 46 ++++++-----
>>   .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 10 ++-
>>   drivers/gpu/drm/i915/gem/i915_gem_mman.c      |  3 +-
>>   drivers/gpu/drm/i915/gem/i915_gem_object.c    | 67 +++++++++++++++-
>>   drivers/gpu/drm/i915/gem/i915_gem_object.h    |  8 ++
>>   .../gpu/drm/i915/gem/i915_gem_object_types.h  | 26 +++++-
>>   drivers/gpu/drm/i915/gem/i915_gem_shmem.c     |  9 ++-
>>   drivers/gpu/drm/i915/gem/i915_gem_shrinker.c  |  2 -
>>   drivers/gpu/drm/i915/gem/i915_gem_stolen.c    |  4 +-
>>   drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c  | 16 ++--
>>   .../gpu/drm/i915/gem/selftests/huge_pages.c   |  2 +-
>>   .../drm/i915/gem/selftests/i915_gem_migrate.c |  2 +-
>>   .../drm/i915/gem/selftests/i915_gem_mman.c    |  2 +-
>>   drivers/gpu/drm/i915/gt/gen6_ppgtt.c          | 10 ++-
>>   drivers/gpu/drm/i915/gt/gen8_ppgtt.c          | 73 +++++++++--------
>>   drivers/gpu/drm/i915/gt/gen8_ppgtt.h          |  3 +-
>>   drivers/gpu/drm/i915/gt/intel_ggtt.c          | 76 +++++++++---------
>>   drivers/gpu/drm/i915/gt/intel_gtt.h           | 20 +++--
>>   drivers/gpu/drm/i915/gt/intel_migrate.c       | 47 ++++++-----
>>   drivers/gpu/drm/i915/gt/intel_migrate.h       | 13 ++-
>>   drivers/gpu/drm/i915/gt/intel_ppgtt.c         |  6 +-
>>   drivers/gpu/drm/i915/gt/selftest_migrate.c    | 47 +++++------
>>   drivers/gpu/drm/i915/gt/selftest_reset.c      |  8 +-
>>   drivers/gpu/drm/i915/gt/selftest_timeline.c   |  2 +-
>>   drivers/gpu/drm/i915/gt/selftest_tlb.c        |  4 +-
>>   drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c      | 10 ++-
>>   drivers/gpu/drm/i915/i915_debugfs.c           | 55 ++++++++++---
>>   drivers/gpu/drm/i915/i915_gem.c               | 16 +++-
>>   drivers/gpu/drm/i915/i915_gpu_error.c         |  8 +-
>>   drivers/gpu/drm/i915/i915_pci.c               | 79 ++++++++++++++++---
>>   drivers/gpu/drm/i915/i915_vma.c               | 16 ++--
>>   drivers/gpu/drm/i915/i915_vma.h               |  2 +-
>>   drivers/gpu/drm/i915/i915_vma_types.h         |  2 -
>>   drivers/gpu/drm/i915/intel_device_info.h      |  5 ++
>>   drivers/gpu/drm/i915/selftests/i915_gem.c     |  5 +-
>>   .../gpu/drm/i915/selftests/i915_gem_evict.c   |  4 +-
>>   drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 15 ++--
>>   .../drm/i915/selftests/intel_memory_region.c  |  4 +-
>>   .../gpu/drm/i915/selftests/mock_gem_device.c  |  9 +++
>>   drivers/gpu/drm/i915/selftests/mock_gtt.c     |  8 +-
>>   include/uapi/drm/i915_drm.h                   | 36 +++++++++
>>   tools/include/uapi/drm/i915_drm.h             | 36 +++++++++
>>   44 files changed, 621 insertions(+), 243 deletions(-)
>>

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