On Thu, Apr 30, 2026 at 12:19 PM Jesse Zhang <[email protected]> wrote: > > From: "Jesse.zhang" <[email protected]> > > Extend AMDGPU_INFO_DOORBELL with an AMDGPU_HW_IP_DMA case so userspace > can discover: > > - The SDMA UMQ doorbell BAR range (index_start..index_end), used to > validate per-queue doorbell offsets. > - Whether an aggregated doorbell slot exists in adev->agdb_bo > (agdb_enable) and its dword offset within that BO (agdb_offset). > > A user-mode driver opens the global aggregated-doorbell BO via > AMDGPU_GEM_OP_OPEN_GLOBAL with AMDGPU_GEM_GLOBAL_AGGREGATED_DOORBELL, > mmaps it, and writes the queue's 32-bit WPTR at the byte offset > agdb_offset * 4 to wake MES — bypassing amdgpu_userq_signal_ioctl > entirely. > > This is the user-visible half of moving the SDMA UMQ wake path out of > the kernel. The kernel-side wake is removed in a follow-up patch. > > Signed-off-by: Jesse Zhang <[email protected]> > ---> drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c > b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c > index a3beeff800bf..1c6368d25b7d 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c > @@ -1437,6 +1437,17 @@ int amdgpu_info_ioctl(struct drm_device *dev, void > *data, struct drm_file *filp) > doorbell_info.index_start = > adev->doorbell_index.vcn.vcn_ring0_1 << 1; > doorbell_info.index_end = > (adev->doorbell_index.vcn.vcn_ring6_7 << 1) + 1; > break; > + case AMDGPU_HW_IP_DMA: > + if (adev->agdb_bo) {
I think this IOCTL should return an error adev->agdb_bo is NULL. We probably also need a per-IP flag to determine if the aggregated doorbell is required or not. That way we can easily support other IP versions that may not require the aggregated doorbell. Can you also add a patch to add doorbell info support for compute and gfx for consistency? Thanks, Alex > + doorbell_info.agdb_enable = 1; > + doorbell_info.agdb_offset = > adev->sdma.agdb_offset; > + } > + doorbell_info.index_start = > + adev->doorbell_index.sdma_engine[0] << 1; > + doorbell_info.index_end = > + > (adev->doorbell_index.sdma_engine[adev->sdma.num_instances - 1] > + << 1) + 1; > + break; > default: > return -EINVAL; > } > -- > 2.49.0 >
