Hi Shixiong,
for drm changes please base your patches on drm-misc-next or drm-next.
That is probably fixed by this one here:
commit b72f66f22c0e39ae6684c43fead774c13db24e73
Author: Christian König <christian.koe...@amd.com>
Date: Tue Feb 11 17:20:53 2025 +0100
dma-buf: drop caching of sg_tables
That was purely for the transition from static to dynamic dma-buf
handling and can be removed again now.
Signed-off-by: Christian König <christian.koe...@amd.com>
Reviewed-by: Simona Vetter <simona.vet...@ffwll.ch>
Reviewed-by: Dmitry Osipenko <dmitry.osipe...@collabora.com>
Link:
https://patchwork.freedesktop.org/patch/msgid/20250211163109.12200-5-christian.koe...@amd.com
After this patch SG tables where only created when necessary.
Regards,
Christian.
On 5/5/25 16:22, oushixiong wrote:
> Hi Christian,
>
> My patch is based on linux-next, so this patch is not based on the latest
> code. Then, I'd like to ask which patch resolved the issue with sg-tables?
>
>
> Thanks and Regards,
>
> Shixiong.
>
>
> 在 2025/5/5 19:25, Christian König 写道:
>> Hi Thomas & Shixiong,
>>
>> first of all the patch is still based on outdated code. For example the
>> cache_sgt_mapping member is already removed in drm-misc-next.
>>
>> So if I'm not completely mistaken the issue is already resolved upstream.
>>
>> Regards,
>> Christian.
>>
>> On 5/5/25 13:12, Thomas Zimmermann wrote:
>>> (cc'ing Christian)
>>>
>>> Hi,
>>>
>>> I don't feel qualified to fully review this patch.
>>>
>>> It would be good to have the issue with sg-tables solved, but I dislike the
>>> dedicated initializer macros. So my question is if this has any drawbacks.
>>> Or could we make this available and the default for all shmem-based drivers?
>>>
>>> Best regards
>>> Thomas
>>>
>>> Am 01.05.25 um 08:43 schrieb oushixiong1...@163.com:
>>>> From: Shixiong Ou <oushixi...@kylinos.cn>
>>>>
>>>> [WHY]
>>>> 1. Drivers using DRM_GEM_SHADOW_PLANE_HELPER_FUNCS and
>>>> DRM_GEM_SHMEM_DRIVER_OPS (e.g., udl, ast) do not require
>>>> sg_table import.
>>>> They only need dma_buf_vmap() to access the shared buffer's
>>>> kernel virtual address.
>>>>
>>>> 2. On certain Aspeed-based boards, a dma_mask of 0xffff_ffff may
>>>> trigger SWIOTLB during dmabuf import. However, IO_TLB_SEGSIZE
>>>> restricts the maximum DMA streaming mapping memory, resulting in
>>>> errors like:
>>>>
>>>> ast 0000:07:00.0: swiotlb buffer is full (sz: 3145728 bytes), total
>>>> 32768 (slots), used 0 (slots)
>>>>
>>>> [HOW]
>>>> Provide a gem_prime_import implementation without sg_table mapping
>>>> to avoid issues (e.g., "swiotlb buffer is full"). Drivers that do not
>>>> require sg_table can adopt this.
>>>>
>>>> Signed-off-by: Shixiong Ou <oushixi...@kylinos.cn>
>>>> ---
>>>> drivers/gpu/drm/drm_gem_shmem_helper.c | 95 ++++++++++++++++++++++++++
>>>> include/drm/drm_gem_shmem_helper.h | 24 +++++++
>>>> 2 files changed, 119 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c
>>>> b/drivers/gpu/drm/drm_gem_shmem_helper.c
>>>> index d99dee67353a..9e41e350ff6f 100644
>>>> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
>>>> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
>>>> @@ -39,6 +39,7 @@ MODULE_IMPORT_NS("DMA_BUF");
>>>> static const struct drm_gem_object_funcs drm_gem_shmem_funcs = {
>>>> .free = drm_gem_shmem_object_free,
>>>> .print_info = drm_gem_shmem_object_print_info,
>>>> + .export = drm_gem_shmem_object_prime_export,
>>>> .pin = drm_gem_shmem_object_pin,
>>>> .unpin = drm_gem_shmem_object_unpin,
>>>> .get_sg_table = drm_gem_shmem_object_get_sg_table,
>>>> @@ -799,6 +800,100 @@ drm_gem_shmem_prime_import_sg_table(struct
>>>> drm_device *dev,
>>>> }
>>>> EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);
>>>> +const struct dma_buf_ops drm_gem_shmem_prime_dmabuf_ops = {
>>>> + .cache_sgt_mapping = true,
>>>> + .attach = drm_gem_map_attach,
>>>> + .detach = drm_gem_map_detach,
>>>> + .map_dma_buf = drm_gem_map_dma_buf,
>>>> + .unmap_dma_buf = drm_gem_unmap_dma_buf,
>>>> + .release = drm_gem_dmabuf_release,
>>>> + .mmap = drm_gem_dmabuf_mmap,
>>>> + .vmap = drm_gem_dmabuf_vmap,
>>>> + .vunmap = drm_gem_dmabuf_vunmap,
>>>> +};
>>>> +
>>>> +/**
>>>> + * drm_gem_shmem_prime_export - implementation of the export callback
>>>> + * @shmem: shmem GEM object
>>>> + */
>>>> +struct dma_buf *drm_gem_shmem_prime_export(struct drm_gem_shmem_object
>>>> *shmem,
>>>> + int flags)
>>>> +{
>>>> + struct drm_gem_object *obj = &shmem->base;
>>>> + struct drm_device *dev = obj->dev;
>>>> + struct dma_buf_export_info exp_info = {
>>>> + .exp_name = KBUILD_MODNAME, /* white lie for debug */
>>>> + .owner = dev->driver->fops->owner,
>>>> + .ops = &drm_gem_shmem_prime_dmabuf_ops,
>>>> + .size = obj->size,
>>>> + .flags = flags,
>>>> + .priv = obj,
>>>> + .resv = obj->resv,
>>>> + };
>>>> +
>>>> + return drm_gem_dmabuf_export(dev, &exp_info);
>>>> +}
>>>> +
>>>> +/**
>>>> + * drm_gem_shmem_prime_import - Import dmabuf without mapping its sg_table
>>>> + * @dev: Device to import into
>>>> + * @dma_buf: dma-buf object to import
>>>> + *
>>>> + * Drivers that use the shmem helpers but also wants to import dmabuf
>>>> without
>>>> + * mapping its sg_table can use this as their &drm_driver.gem_prime_import
>>>> + * implementation.
>>>> + */
>>>> +struct drm_gem_object *drm_gem_shmem_prime_import(struct drm_device *dev,
>>>> + struct dma_buf *dma_buf)
>>>> +{
>>>> + struct dma_buf_attachment *attach;
>>>> + struct drm_gem_shmem_object *shmem;
>>>> + size_t size;
>>>> + int ret;
>>>> +
>>>> + if (dma_buf->ops == &drm_gem_shmem_prime_dmabuf_ops) {
>>>> + struct drm_gem_object *obj;
>>>> +
>>>> + obj = dma_buf->priv;
>>>> + if (obj->dev == dev) {
>>>> + /*
>>>> + * Importing dmabuf exported from our own gem increases
>>>> + * refcount on gem itself instead of f_count of dmabuf.
>>>> + */
>>>> + drm_gem_object_get(obj);
>>>> + return obj;
>>>> + }
>>>> + }
>>>> +
>>>> + attach = dma_buf_attach(dma_buf, dev->dev);
>>>> + if (IS_ERR(attach))
>>>> + return ERR_CAST(attach);
>>>> +
>>>> + get_dma_buf(dma_buf);
>>>> +
>>>> + size = PAGE_ALIGN(attach->dmabuf->size);
>>>> +
>>>> + shmem = __drm_gem_shmem_create(dev, size, true, NULL);
>>>> + if (IS_ERR(shmem)) {
>>>> + ret = PTR_ERR(shmem);
>>>> + goto fail_detach;
>>>> + }
>>>> +
>>>> + drm_dbg_prime(dev, "size = %zu\n", size);
>>>> +
>>>> + shmem->base.import_attach = attach;
>>>> + shmem->base.resv = dma_buf->resv;
>>>> +
>>>> + return &shmem->base;
>>>> +
>>>> +fail_detach:
>>>> + dma_buf_detach(dma_buf, attach);
>>>> + dma_buf_put(dma_buf);
>>>> +
>>>> + return ERR_PTR(ret);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import);
>>>> +
>>>> MODULE_DESCRIPTION("DRM SHMEM memory-management helpers");
>>>> MODULE_IMPORT_NS("DMA_BUF");
>>>> MODULE_LICENSE("GPL v2");
>>>> diff --git a/include/drm/drm_gem_shmem_helper.h
>>>> b/include/drm/drm_gem_shmem_helper.h
>>>> index cef5a6b5a4d6..78ef91593a8e 100644
>>>> --- a/include/drm/drm_gem_shmem_helper.h
>>>> +++ b/include/drm/drm_gem_shmem_helper.h
>>>> @@ -110,6 +110,8 @@ int drm_gem_shmem_vmap(struct drm_gem_shmem_object
>>>> *shmem,
>>>> void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
>>>> struct iosys_map *map);
>>>> int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct
>>>> vm_area_struct *vma);
>>>> +struct dma_buf *drm_gem_shmem_prime_export(struct drm_gem_shmem_object
>>>> *shmem,
>>>> + int flags);
>>>> int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem);
>>>> void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem);
>>>> @@ -168,6 +170,18 @@ static inline void
>>>> drm_gem_shmem_object_print_info(struct drm_printer *p, unsign
>>>> drm_gem_shmem_print_info(shmem, p, indent);
>>>> }
>>>> +/**
>>>> + * drm_gem_shmem_object_prime_export - GEM object function for export()
>>>> + * @obj: GEM object
>>>> + *
>>>> + */
>>>> +static inline struct dma_buf *drm_gem_shmem_object_prime_export(struct
>>>> drm_gem_object *obj,
>>>> + int flags)
>>>> +{
>>>> + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
>>>> +
>>>> + return drm_gem_shmem_prime_export(shmem, flags);
>>>> +}
>>>> /**
>>>> * drm_gem_shmem_object_pin - GEM object function for
>>>> drm_gem_shmem_pin()
>>>> * @obj: GEM object
>>>> @@ -276,6 +290,8 @@ drm_gem_shmem_prime_import_sg_table(struct drm_device
>>>> *dev,
>>>> struct sg_table *sgt);
>>>> int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device
>>>> *dev,
>>>> struct drm_mode_create_dumb *args);
>>>> +struct drm_gem_object *drm_gem_shmem_prime_import(struct drm_device *dev,
>>>> + struct dma_buf *buf);
>>>> /**
>>>> * DRM_GEM_SHMEM_DRIVER_OPS - Default shmem GEM operations
>>>> @@ -287,4 +303,12 @@ int drm_gem_shmem_dumb_create(struct drm_file *file,
>>>> struct drm_device *dev,
>>>> .gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table, \
>>>> .dumb_create = drm_gem_shmem_dumb_create
>>>> +/**
>>>> + * This macro provides a shmem GEM operations that implementate a simple
>>>> + * gem_prime_import.
>>>> + */
>>>> +#define DRM_GEM_SHMEM_SIMPLE_DRIVER_OPS \
>>>> + .gem_prime_import = drm_gem_shmem_prime_import, \
>>>> + .dumb_create = drm_gem_shmem_dumb_create
>>>> +
>>>> #endif /* __DRM_GEM_SHMEM_HELPER_H__ */
>
