It comes from amdgpu_query_gpu_info_init()

        for (i = 0; i < (int)dev->info.num_shader_engines; i++) {
                unsigned instance = (i << AMDGPU_INFO_MMR_SE_INDEX_SHIFT) |
                                    (AMDGPU_INFO_MMR_SH_INDEX_MASK <<

                r = amdgpu_read_mm_registers(dev, 0x263d, 1, instance, 0,

This effectively reads from 0/* where the kernel adds the instance of * so it's 
0/*/*.  That line was last changed  by Alex

0936139536380 (Alex Deucher  2015-04-20 12:04:22 -0400 174)                     

I still don't get why this is a reason to hit pause on the patch(es) though.  
They're root only, you can still not use * if you don't want to and furthermore 
I'm already using the write debugfs content (to debug waveforms).


From: Michel Dänzer <>
Sent: Tuesday, October 11, 2016 20:34
To: StDenis, Tom; Christian König
Subject: Re: [PATCH] drm/amd/amdgpu: Allow broadcast on debugfs read (v2)

On 11/10/16 09:32 PM, StDenis, Tom wrote:
> It's used by the UMD though they read from 0/*/* when reading the
> RASTER_CONFIG registers (which may be a bug...)

We should probably clarify what userspace is trying to do there, and
whether the hardware actually does that.

Earthling Michel Dänzer               |     
Graphics, Processors and Immersive VR Solutions | AMD <>
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