That's not why it was removed. It was removed because userspace doesn't use
GDS memory and gds_va is always going to be 0.
Firmware shouldn't use it because using it would increase preemption
latency.
Marek
On Sun, Apr 9, 2023, 11:21 Christian König <ckoenig.leichtzumer...@gmail.com>
wrote:
> We removed the GDS information because they were unnecessary. The GDS size
> was already part of the device info before we added the shadow info.
>
> But as far as I know the firmware needs valid VAs for all three buffers or
> won't work correctly.
>
> Christian.
>
> Am 06.04.23 um 17:01 schrieb Marek Olšák:
>
> There is no GDS shadowing info in the device info uapi, so userspace can't
> create any GDS buffer and thus can't have any GDS va. It's a uapi issue,
> not what firmware wants to do.
>
> Marek
>
> On Thu, Apr 6, 2023 at 6:31 AM Christian König <
> ckoenig.leichtzumer...@gmail.com> wrote:
>
>> That's what I thought as well, but Mitch/Hans insisted on that.
>>
>> We should probably double check internally.
>>
>> Christian.
>>
>> Am 06.04.23 um 11:43 schrieb Marek Olšák:
>>
>> GDS memory isn't used on gfx11. Only GDS OA is used.
>>
>> Marek
>>
>> On Thu, Apr 6, 2023 at 5:09 AM Christian König <christian.koe...@amd.com>
>> wrote:
>>
>>> Why that?
>>>
>>> This is the save buffer for GDS, not the old style GDS BOs.
>>>
>>> Christian.
>>>
>>> Am 06.04.23 um 09:36 schrieb Marek Olšák:
>>>
>>> gds_va is unnecessary.
>>>
>>> Marek
>>>
>>> On Thu, Mar 30, 2023 at 3:18 PM Alex Deucher <alexander.deuc...@amd.com>
>>> wrote:
>>>
>>>> For GFX11, the UMD needs to allocate some shadow buffers
>>>> to be used for preemption. The UMD allocates the buffers
>>>> and passes the GPU virtual address to the kernel since the
>>>> kernel will program the packet that specified these
>>>> addresses as part of its IB submission frame.
>>>>
>>>> v2: UMD passes shadow init to tell kernel when to initialize
>>>> the shadow
>>>>
>>>> Reviewed-by: Christian König <christian.koe...@amd.com>
>>>> Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
>>>> ---
>>>> include/uapi/drm/amdgpu_drm.h | 10 ++++++++++
>>>> 1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/include/uapi/drm/amdgpu_drm.h
>>>> b/include/uapi/drm/amdgpu_drm.h
>>>> index b6eb90df5d05..3d9474af6566 100644
>>>> --- a/include/uapi/drm/amdgpu_drm.h
>>>> +++ b/include/uapi/drm/amdgpu_drm.h
>>>> @@ -592,6 +592,7 @@ struct drm_amdgpu_gem_va {
>>>> #define AMDGPU_CHUNK_ID_SCHEDULED_DEPENDENCIES 0x07
>>>> #define AMDGPU_CHUNK_ID_SYNCOBJ_TIMELINE_WAIT 0x08
>>>> #define AMDGPU_CHUNK_ID_SYNCOBJ_TIMELINE_SIGNAL 0x09
>>>> +#define AMDGPU_CHUNK_ID_CP_GFX_SHADOW 0x0a
>>>>
>>>> struct drm_amdgpu_cs_chunk {
>>>> __u32 chunk_id;
>>>> @@ -708,6 +709,15 @@ struct drm_amdgpu_cs_chunk_data {
>>>> };
>>>> };
>>>>
>>>> +#define AMDGPU_CS_CHUNK_CP_GFX_SHADOW_FLAGS_INIT_SHADOW 0x1
>>>> +
>>>> +struct drm_amdgpu_cs_chunk_cp_gfx_shadow {
>>>> + __u64 shadow_va;
>>>> + __u64 csa_va;
>>>> + __u64 gds_va;
>>>> + __u64 flags;
>>>> +};
>>>> +
>>>> /*
>>>> * Query h/w info: Flag that this is integrated (a.h.a. fusion) GPU
>>>> *
>>>> --
>>>> 2.39.2
>>>>
>>>>
>>>
>>
>
