[PATCH v4 2/3] drm/amdgpu: Reset the clear flag in buddy during resume
Arunpravin Paneer Selvam
arunpravin.paneerselvam at amd.com
Wed Jul 16 07:53:58 UTC 2025
On 7/16/2025 1:21 PM, Christian König wrote:
> On 16.07.25 09:41, Arunpravin Paneer Selvam wrote:
>> - Added a handler in DRM buddy manager to reset the cleared
>> flag for the blocks in the freelist.
>>
>> - This is necessary because, upon resuming, the VRAM becomes
>> cluttered with BIOS data, yet the VRAM backend manager
>> believes that everything has been cleared.
>>
>> v2:
>> - Add lock before accessing drm_buddy_clear_reset_blocks()(Matthew Auld)
>> - Force merge the two dirty blocks.(Matthew Auld)
>> - Add a new unit test case for this issue.(Matthew Auld)
>> - Having this function being able to flip the state either way would be
>> good. (Matthew Brost)
>>
>> v3(Matthew Auld):
>> - Do merge step first to avoid the use of extra reset flag.
> You've lost me with that :)
Just realized after sending this mail. Added in v5 :)
Thank you,
Arun.
>
>> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
>> Suggested-by: Christian König <christian.koenig at amd.com>
>> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
>> Cc: stable at vger.kernel.org
>> Fixes: a68c7eaa7a8f ("drm/amdgpu: Enable clear page functionality")
>> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3812
> Acked-by: Christian König <christian.koenig at amd.com>
>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +
>> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 1 +
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 17 ++++++++
>> drivers/gpu/drm/drm_buddy.c | 43 ++++++++++++++++++++
>> include/drm/drm_buddy.h | 2 +
>> 5 files changed, 65 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index 723ab95d8c48..ac92220f9fc3 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -5327,6 +5327,8 @@ int amdgpu_device_resume(struct drm_device *dev, bool notify_clients)
>> dev->dev->power.disable_depth--;
>> #endif
>> }
>> +
>> + amdgpu_vram_mgr_clear_reset_blocks(adev);
>> adev->in_suspend = false;
>>
>> if (amdgpu_acpi_smart_shift_update(dev, AMDGPU_SS_DEV_D0))
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> index 215c198e4aff..2309df3f68a9 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> @@ -155,6 +155,7 @@ int amdgpu_vram_mgr_reserve_range(struct amdgpu_vram_mgr *mgr,
>> uint64_t start, uint64_t size);
>> int amdgpu_vram_mgr_query_page_status(struct amdgpu_vram_mgr *mgr,
>> uint64_t start);
>> +void amdgpu_vram_mgr_clear_reset_blocks(struct amdgpu_device *adev);
>>
>> bool amdgpu_res_cpu_visible(struct amdgpu_device *adev,
>> struct ttm_resource *res);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>> index abdc52b0895a..07c936e90d8e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>> @@ -782,6 +782,23 @@ uint64_t amdgpu_vram_mgr_vis_usage(struct amdgpu_vram_mgr *mgr)
>> return atomic64_read(&mgr->vis_usage);
>> }
>>
>> +/**
>> + * amdgpu_vram_mgr_clear_reset_blocks - reset clear blocks
>> + *
>> + * @adev: amdgpu device pointer
>> + *
>> + * Reset the cleared drm buddy blocks.
>> + */
>> +void amdgpu_vram_mgr_clear_reset_blocks(struct amdgpu_device *adev)
>> +{
>> + struct amdgpu_vram_mgr *mgr = &adev->mman.vram_mgr;
>> + struct drm_buddy *mm = &mgr->mm;
>> +
>> + mutex_lock(&mgr->lock);
>> + drm_buddy_reset_clear(mm, false);
>> + mutex_unlock(&mgr->lock);
>> +}
>> +
>> /**
>> * amdgpu_vram_mgr_intersects - test each drm buddy block for intersection
>> *
>> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
>> index a1e652b7631d..a94061f373de 100644
>> --- a/drivers/gpu/drm/drm_buddy.c
>> +++ b/drivers/gpu/drm/drm_buddy.c
>> @@ -405,6 +405,49 @@ drm_get_buddy(struct drm_buddy_block *block)
>> }
>> EXPORT_SYMBOL(drm_get_buddy);
>>
>> +/**
>> + * drm_buddy_reset_clear - reset blocks clear state
>> + *
>> + * @mm: DRM buddy manager
>> + * @is_clear: blocks clear state
>> + *
>> + * Reset the clear state based on @is_clear value for each block
>> + * in the freelist.
>> + */
>> +void drm_buddy_reset_clear(struct drm_buddy *mm, bool is_clear)
>> +{
>> + u64 root_size, size, start;
>> + unsigned int order;
>> + int i;
>> +
>> + size = mm->size;
>> + for (i = 0; i < mm->n_roots; ++i) {
>> + order = ilog2(size) - ilog2(mm->chunk_size);
>> + start = drm_buddy_block_offset(mm->roots[i]);
>> + __force_merge(mm, start, start + size, order);
>> +
>> + root_size = mm->chunk_size << order;
>> + size -= root_size;
>> + }
>> +
>> + for (i = 0; i <= mm->max_order; ++i) {
>> + struct drm_buddy_block *block;
>> +
>> + list_for_each_entry_reverse(block, &mm->free_list[i], link) {
>> + if (is_clear != drm_buddy_block_is_clear(block)) {
>> + if (is_clear) {
>> + mark_cleared(block);
>> + mm->clear_avail += drm_buddy_block_size(mm, block);
>> + } else {
>> + clear_reset(block);
>> + mm->clear_avail -= drm_buddy_block_size(mm, block);
>> + }
>> + }
>> + }
>> + }
>> +}
>> +EXPORT_SYMBOL(drm_buddy_reset_clear);
>> +
>> /**
>> * drm_buddy_free_block - free a block
>> *
>> diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
>> index 9689a7c5dd36..513837632b7d 100644
>> --- a/include/drm/drm_buddy.h
>> +++ b/include/drm/drm_buddy.h
>> @@ -160,6 +160,8 @@ int drm_buddy_block_trim(struct drm_buddy *mm,
>> u64 new_size,
>> struct list_head *blocks);
>>
>> +void drm_buddy_reset_clear(struct drm_buddy *mm, bool is_clear);
>> +
>> void drm_buddy_free_block(struct drm_buddy *mm, struct drm_buddy_block *block);
>>
>> void drm_buddy_free_list(struct drm_buddy *mm,
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