[PATCH] drm/amdgpu: fix the ib test hang when gfx is in "idle" state

[Huang Rui]

On Fri, Apr 20, 2018 at 05:59:16PM +0800, Koenig, Christian wrote:
> Am 20.04.2018 um 11:40 schrieb Huang Rui:
> > "aaabaf4   drm/amdgpu: defer test IBs on the rings at boot (V3)"
> > Above patch defers the execution of gfx/compute ib tests. However, at that time,
> > the gfx may already go into idle state. If "idle" gfx receives command
> > submission, it will get hang in the system. So we must add is_gfx_on checking at
> > start of ib tests.
> 
> Do I see that right that you just skip the IB test when the GFX block is 
> already turned of? In this case that would be a clear NAK.
> 
> BTW: How do you detect that we need to turn GFX on again?

Christian, I know point. But there is a hang issue if we would like try to
disable/enable gfxoff with SMC message at runtime. Actually, I am trying to
find a good sequence to fix it. After that, I can even expose an debugfs
interface to configure that. So I have to skip the test for the moment when
gfx is in "idle".

Thanks,
Ray