Bug 103921

Summary:	llvmpipe consume all resources on GPU Vega RX (amdgpu driver) with mesa 17.2.4 if disabled IGPU
Product:	Mesa	Reporter:	mikhail.v.gavrilov
Component:	Mesa core	Assignee:	mesa-dev
Status:	RESOLVED NOTABUG	QA Contact:	mesa-dev
Severity:	normal
Priority:	medium
Version:	17.2
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description mikhail.v.gavrilov 2017-11-26 20:58:47 UTC

How reproduce:
1. On Fedora 27 compile and install latest amdgpu driver from branch amd-staging-drm-next by this instruction https://fedoraproject.org/wiki/Building_a_custom_kernel
Or install mainline vanilla kernel from this repo https://fedoraproject.org/wiki/Kernel_Vanilla_Repositories
If you don't make this step Vega RX would be runned under VESA driver which don't have this issue.
2. By default Fedora 27 shipped with mesa 17.2.4, don't update it to 17.4 from CORP repo.
3. Restart computer.
4. Goto BIOS and disable IGPU if it was enabled.


Expected result: llvmpipe should work with amdgpu same as with VESA driver without consuming all CPU resources.


Interesting note:
If go in BIOS and enable Intel GPU graphics without without reconnecting monitor to mother board (means monitor still connected to Radeon VEGA RX card) then this issue is gone. Why? In this case still used llvmpipe and amdgpu driver.


Demonstration: https://youtu.be/rFDeR8-_yMo

Comment 1 Timothy Arceri 2018-04-10 05:40:08 UTC

You want to be using radeonsi not llvmpipe. llvmpipe is a software renderer and will indeed be slow.

Comment 2 mikhail.v.gavrilov 2018-04-10 05:50:31 UTC

You don't understand me.
I know how llvmpipe work.
I just want to say that in described case llvmpipe consume resources abnormaly (mean much more than usual)

Comment 3 mikhail.v.gavrilov 2018-04-10 05:53:11 UTC

> llvmpipe should work with amdgpu same as with VESA driver without consuming all CPU resources.

it means llvmpipe with vesa driver is possible use but llvmpipe with amdgpu impossible use because driver consume for unknown reason much more resources than with vesa driver.

Comment 4 Timothy Arceri 2018-04-10 06:16:07 UTC

(In reply to mikhail.v.gavrilov from comment #3)
> > llvmpipe should work with amdgpu same as with VESA driver without consuming all CPU resources.
> 
> it means llvmpipe with vesa driver is possible use but llvmpipe with amdgpu
> impossible use because driver consume for unknown reason much more resources
> than with vesa driver.

My guess is that you end up with a higher resolution desktop when using amdgpu. With my 4K monitor llvmpipe is extremely slow.

Comment 5 mikhail.v.gavrilov 2018-04-10 06:20:50 UTC

> My guess is that you end up with a higher resolution desktop when using amdgpu. With my 4K monitor llvmpipe is extremely slow.

Of course I tested VESA and AMDGPU with the same resolution Full HD.
It just seems suspicious to me that the VESA driver works much better with llvmpipe than AMDGPU on same resolution.

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