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    Well that approach was discussed before and seemed to be to
    complicated.<br>
    <br>
    But I totally agree that the AMDGPU_GEM_CREATE_GFX12_DCC flag is a
    bad idea. This isn't anything userspace should need to specify in
    the first place.<br>
    <br>
    All we need is a hardware workaround which kicks in all the time
    while pinning BOs for this specific hw generation and texture
    channel configuration.<br>
    <br>
    Please remove the AMDGPU_GEM_CREATE_GFX12_DCC flag again if possible
    or specify why it is actually necessary?<br>
    <br>
    Regards,<br>
    Christian.<br>
    <br>
    <div class="moz-cite-prefix">Am 17.07.24 um 05:44 schrieb Marek
      Olšák:<br>
    </div>
    <blockquote type="cite" cite="mid:CAAxE2A6gpvLcq7zDhTDgV1BiBZdbK6t7147ESpq0ufYqW-6gzQ@mail.gmail.com">
      
      <div dir="auto">
        <div>AMDGPU_GEM_CREATE_GFX12_DCC is set on 90% of all memory
          allocations, and almost all of them are not displayable.
          Shouldn't we use a different way to indicate that we need a
          non-power-of-two alignment, such as looking at the alignment
          field directly? </div>
        <div dir="auto"><br>
        </div>
        <div dir="auto">Marek<br>
          <br>
          <div class="gmail_quote" dir="auto">
            <div dir="ltr" class="gmail_attr">On Tue, Jul 16, 2024,
              11:45 Arunpravin Paneer Selvam <<a href="mailto:Arunpravin.PaneerSelvam@amd.com" moz-do-not-send="true" class="moz-txt-link-freetext">Arunpravin.PaneerSelvam@amd.com</a>>
              wrote:<br>
            </div>
            <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Add
              address alignment support to the DCC VRAM buffers.<br>
              <br>
              v2:<br>
                - adjust size based on the max_texture_channel_caches
              values<br>
                  only for GFX12 DCC buffers.<br>
                - used AMDGPU_GEM_CREATE_GFX12_DCC flag to apply change
              only<br>
                  for DCC buffers.<br>
                - roundup non power of two DCC buffer adjusted size to
              nearest<br>
                  power of two number as the buddy allocator does not
              support non<br>
                  power of two alignments. This applies only to the
              contiguous<br>
                  DCC buffers.<br>
              <br>
              v3:(Alex)<br>
                - rewrite the max texture channel caches comparison code
              in an<br>
                  algorithmic way to determine the alignment size.<br>
              <br>
              v4:(Alex)<br>
                - Move the logic from amdgpu_vram_mgr_dcc_alignment() to
              gmc_v12_0.c<br>
                  and add a new gmc func callback for dcc alignment. If
              the callback<br>
                  is non-NULL, call it to get the alignment, otherwise,
              use the default.<br>
              <br>
              v5:(Alex)<br>
                - Set the Alignment to a default value if the callback
              doesn't exist.<br>
                - Add the callback to amdgpu_gmc_funcs.<br>
              <br>
              v6:<br>
                - Fix checkpatch error reported by Intel CI.<br>
              <br>
              Signed-off-by: Arunpravin Paneer Selvam <<a href="mailto:Arunpravin.PaneerSelvam@amd.com" target="_blank" rel="noreferrer" moz-do-not-send="true" class="moz-txt-link-freetext">Arunpravin.PaneerSelvam@amd.com</a>><br>
              Acked-by: Alex Deucher <<a href="mailto:alexander.deucher@amd.com" target="_blank" rel="noreferrer" moz-do-not-send="true" class="moz-txt-link-freetext">alexander.deucher@amd.com</a>><br>
              Acked-by: Christian König <<a href="mailto:christian.koenig@amd.com" target="_blank" rel="noreferrer" moz-do-not-send="true" class="moz-txt-link-freetext">christian.koenig@amd.com</a>><br>
              Reviewed-by: Frank Min <<a href="mailto:Frank.Min@amd.com" target="_blank" rel="noreferrer" moz-do-not-send="true" class="moz-txt-link-freetext">Frank.Min@amd.com</a>><br>
              ---<br>
               drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h      |  6 ++++<br>
               drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 36
              ++++++++++++++++++--<br>
               drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c       | 15
              ++++++++<br>
               3 files changed, 55 insertions(+), 2 deletions(-)<br>
              <br>
              diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
              b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h<br>
              index febca3130497..654d0548a3f8 100644<br>
              --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h<br>
              +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h<br>
              @@ -156,6 +156,8 @@ struct amdgpu_gmc_funcs {<br>
                                                    uint64_t addr,
              uint64_t *flags);<br>
                      /* get the amount of memory used by the vbios for
              pre-OS console */<br>
                      unsigned int (*get_vbios_fb_size)(struct
              amdgpu_device *adev);<br>
              +       /* get the DCC buffer alignment */<br>
              +       u64 (*get_dcc_alignment)(struct amdgpu_device
              *adev);<br>
              <br>
                      enum amdgpu_memory_partition
              (*query_mem_partition_mode)(<br>
                              struct amdgpu_device *adev);<br>
              @@ -363,6 +365,10 @@ struct amdgpu_gmc {<br>
                     
              (adev)->gmc.gmc_funcs->override_vm_pte_flags       
                          \<br>
                              ((adev), (vm), (addr), (pte_flags))<br>
               #define amdgpu_gmc_get_vbios_fb_size(adev)
              (adev)->gmc.gmc_funcs->get_vbios_fb_size((adev))<br>
              +#define amdgpu_gmc_get_dcc_alignment(_adev) ({           
                   \<br>
              +       typeof(_adev) (adev) = (_adev);                   
                   \<br>
              +     
               ((adev)->gmc.gmc_funcs->get_dcc_alignment((adev))); 
                 \<br>
              +})<br>
              <br>
               /**<br>
                * amdgpu_gmc_vram_full_visible - Check if full VRAM is
              visible through the BAR<br>
              diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
              b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c<br>
              index f91cc149d06c..aa9dca12371c 100644<br>
              --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c<br>
              +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c<br>
              @@ -512,6 +512,16 @@ static int amdgpu_vram_mgr_new(struct
              ttm_resource_manager *man,<br>
                              vres->flags |=
              DRM_BUDDY_RANGE_ALLOCATION;<br>
              <br>
                      remaining_size = (u64)vres->base.size;<br>
              +       if (bo->flags &
              AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS &&<br>
              +           bo->flags &
              AMDGPU_GEM_CREATE_GFX12_DCC) {<br>
              +               u64 adjust_size;<br>
              +<br>
              +               if
              (adev->gmc.gmc_funcs->get_dcc_alignment) {<br>
              +                       adjust_size =
              amdgpu_gmc_get_dcc_alignment(adev);<br>
              +                       remaining_size =
              roundup_pow_of_two(remaining_size + adjust_size);<br>
              +                       vres->flags |=
              DRM_BUDDY_TRIM_DISABLE;<br>
              +               }<br>
              +       }<br>
              <br>
                      mutex_lock(&mgr->lock);<br>
                      while (remaining_size) {<br>
              @@ -521,8 +531,12 @@ static int amdgpu_vram_mgr_new(struct
              ttm_resource_manager *man,<br>
                                      min_block_size =
              mgr->default_page_size;<br>
              <br>
                              size = remaining_size;<br>
              -               if ((size >= (u64)pages_per_block
              << PAGE_SHIFT) &&<br>
              -                   !(size & (((u64)pages_per_block
              << PAGE_SHIFT) - 1)))<br>
              +<br>
              +               if (bo->flags &
              AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS &&<br>
              +                   bo->flags &
              AMDGPU_GEM_CREATE_GFX12_DCC)<br>
              +                       min_block_size = size;<br>
              +               else if ((size >= (u64)pages_per_block
              << PAGE_SHIFT) &&<br>
              +                        !(size &
              (((u64)pages_per_block << PAGE_SHIFT) - 1)))<br>
                                      min_block_size =
              (u64)pages_per_block << PAGE_SHIFT;<br>
              <br>
                              BUG_ON(min_block_size <
              mm->chunk_size);<br>
              @@ -553,6 +567,24 @@ static int amdgpu_vram_mgr_new(struct
              ttm_resource_manager *man,<br>
                      }<br>
                      mutex_unlock(&mgr->lock);<br>
              <br>
              +       if (bo->flags &
              AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS &&<br>
              +           bo->flags &
              AMDGPU_GEM_CREATE_GFX12_DCC) {<br>
              +               struct drm_buddy_block *dcc_block;<br>
              +               u64 dcc_start, alignment;<br>
              +<br>
              +               dcc_block =
              amdgpu_vram_mgr_first_block(&vres->blocks);<br>
              +               dcc_start =
              amdgpu_vram_mgr_block_start(dcc_block);<br>
              +<br>
              +               if
              (adev->gmc.gmc_funcs->get_dcc_alignment) {<br>
              +                       alignment =
              amdgpu_gmc_get_dcc_alignment(adev);<br>
              +                       /* Adjust the start address for
              DCC buffers only */<br>
              +                       dcc_start = roundup(dcc_start,
              alignment);<br>
              +                       drm_buddy_block_trim(mm,
              &dcc_start,<br>
              +                                           
              (u64)vres->base.size,<br>
              +                                           
              &vres->blocks);<br>
              +               }<br>
              +       }<br>
              +<br>
                      vres->base.start = 0;<br>
                      size = max_t(u64,
              amdgpu_vram_mgr_blocks_size(&vres->blocks),<br>
                                   vres->base.size);<br>
              diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c
              b/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c<br>
              index fd3ac483760e..4259edcdec8a 100644<br>
              --- a/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c<br>
              +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c<br>
              @@ -542,6 +542,20 @@ static unsigned
              gmc_v12_0_get_vbios_fb_size(struct amdgpu_device *adev)<br>
                      return 0;<br>
               }<br>
              <br>
              +static u64 gmc_v12_0_get_dcc_alignment(struct
              amdgpu_device *adev)<br>
              +{<br>
              +       u64 max_tex_channel_caches, alignment;<br>
              +<br>
              +       max_tex_channel_caches =
              adev->gfx.config.max_texture_channel_caches;<br>
              +       if (is_power_of_2(max_tex_channel_caches))<br>
              +               alignment = (max_tex_channel_caches /
              SZ_4) * max_tex_channel_caches;<br>
              +       else<br>
              +               alignment =
              roundup_pow_of_two(max_tex_channel_caches) *<br>
              +                               max_tex_channel_caches;<br>
              +<br>
              +       return (u64)alignment * SZ_1K;<br>
              +}<br>
              +<br>
               static const struct amdgpu_gmc_funcs gmc_v12_0_gmc_funcs
              = {<br>
                      .flush_gpu_tlb = gmc_v12_0_flush_gpu_tlb,<br>
                      .flush_gpu_tlb_pasid =
              gmc_v12_0_flush_gpu_tlb_pasid,<br>
              @@ -551,6 +565,7 @@ static const struct amdgpu_gmc_funcs
              gmc_v12_0_gmc_funcs = {<br>
                      .get_vm_pde = gmc_v12_0_get_vm_pde,<br>
                      .get_vm_pte = gmc_v12_0_get_vm_pte,<br>
                      .get_vbios_fb_size = gmc_v12_0_get_vbios_fb_size,<br>
              +       .get_dcc_alignment = gmc_v12_0_get_dcc_alignment,<br>
               };<br>
              <br>
               static void gmc_v12_0_set_gmc_funcs(struct amdgpu_device
              *adev)<br>
              -- <br>
              2.25.1<br>
              <br>
            </blockquote>
          </div>
        </div>
      </div>
    </blockquote>
    <br>
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