On 5/1/26 15:30, Alex Deucher wrote:
> On Thu, Apr 30, 2026 at 12:29 PM Jesse Zhang <[email protected]> wrote:
>>
>> From: "Jesse.zhang" <[email protected]>
>>
>> Pair the userspace aggregated-doorbell ring (added by the
>> AMDGPU_INFO_DOORBELL / AMDGPU_GEM_GLOBAL_AGGREGATED_DOORBELL ABI in
>> the previous patches) with a kernel-side
>> MES_MISC_OP_NOTIFY_WORK_ON_UNMAPPED_QUEUE in amdgpu_userq_signal_ioctl
>> for SDMA UMQs.
>>
>> Signed-off-by: Jesse Zhang <[email protected]>
>
> How will this work if the user doesn't use this IOCTL? protected
> fences are optional. An application can create a user queue and never
> use a protected fence. Why don't KFD SDMA queues need this special
> treatment?
Yeah agree that whole approach doesn't work.
What we could do is similar to the MM queues that userspace need to signal both
a per queue doorbell and an aggregated one for the queue type.
Regards,
Christian.
>
> Alex
>
>> ---
>> .../gpu/drm/amd/amdgpu/amdgpu_userq_fence.c | 29 +++++++++++++++++++
>> 1 file changed, 29 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
>> index a58342c2ac44..50e275b51c9e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
>> @@ -598,6 +598,35 @@ int amdgpu_userq_signal_ioctl(struct drm_device *dev,
>> void *data,
>> /* drop the reference acquired in fence creation function */
>> dma_fence_put(fence);
>>
>> + /*
>> + * SDMA UMQ wake: SDMA has no CP_UNMAPPED_DOORBELL HW intercept, so
>> + * once MES gangs the queue out (after the first IB's PROTECTED_FENCE
>> + * idles the queue), per-queue doorbell rings hit a mapped-out HW
>> + * slot and are silently dropped — FENCE IRQ never fires.
>> + *
>> + * Userspace rings the priority's MES aggregated doorbell directly
>> + * via the agdb_bo mmap (see AMDGPU_INFO_DOORBELL +
>> + * AMDGPU_GEM_GLOBAL_AGGREGATED_DOORBELL). That alone, however, is
>> + * not enough on current MES12 firmware — MES will not scan the
>> + * priority's queue list unless its hasReadyQueues flag is set.
>> + * NOTIFY_WORK_ON_UNMAPPED_QUEUE flips that flag, so MES then
>> + * processes the doorbell ring and re-MAP_QUEUEs the SDMA UMQ.
>> + *
>> + * This is a kernel-side companion to the userspace agg doorbell
>> + * ring; remove once firmware learns to wake on bare aggregated
>> + * doorbell.
>> + */
>> + if (queue && queue->queue_type == AMDGPU_HW_IP_DMA &&
>> + adev->enable_mes && adev->mes.funcs->misc_op) {
>> + struct mes_misc_op_input op = { 0 };
>> +
>> + op.op = MES_MISC_OP_NOTIFY_WORK_ON_UNMAPPED_QUEUE;
>> + op.notify_work.priority_level =
>> AMDGPU_MES_PRIORITY_LEVEL_NORMAL;
>> + amdgpu_mes_lock(&adev->mes);
>> + (void)adev->mes.funcs->misc_op(&adev->mes, &op);
>> + amdgpu_mes_unlock(&adev->mes);
>> + }
>> +
>> exec_fini:
>> drm_exec_fini(&exec);
>> put_gobj_write:
>> --
>> 2.49.0
>>
