On Fri, Apr 20, 2018 at 01:58:33AM +0800, Kuehling, Felix wrote: > On 2018-04-19 09:51 AM, Alex Deucher wrote: > > On Wed, Apr 18, 2018 at 8:22 PM, Huang Rui <ray.huang at amd.com> wrote: > >> GFXOFF is the new GPU feature that save power consumption. It used RLC to > >> poweroff the gfx engine dynamicly when there is no workload on gfx pipe and make > >> gfx into "idle" state. > >> 1. Add three additional RLC ucodes, and use psp to load them. > >> 2. Revise RLC save restore list. > >> 3. Enable CGPG (GFX power gating). > >> 4. Enable gfxoff. > >> 5. Revise suspend/resume sequence. > >> > >> Currently, only raven is able to support gfxoff at first. And after CQE do > >> series rounds of testing, and there is no regression that bring by gfxoff > >> feature till now. > >> > >> We support two types of gfxoff, and user is able to build them manually from > >> firmware repo: > >> 1. Real CGPG > >> $ make clean > >> $ make REAL_CGPG=1 > >> 2. Faked CGPG: (by default) > >> $ make clean > >> $ make > >> > >> Then configure to enable gfxoff with ppfeaturemask=0xffffbfff. > > A couple of things we need to take care of before enabling this: > > 1. Need to switch it off when selecting stable pstate or profiling > > mode in powerplay > > 2. Need to check if gfx is on before accessing the RLC_GPU_CLOCK_COUNT > > registers. > > I second that. Access to RLC_GPU_CLOCK_COUNT is used for some ROCm > profiling features. Accessing the register while GFX is OFF can lead to > hangs according to HW engineers. Also, GFX OFF resets the counter to 0, > which would confuse any profiling code using it. > > Would it be possible to control the GFX OFF feature as part of power > profiles? For example we could have the feature disabled in the compute > power profile. > Yes, you're right. We have to take care the runtime RLC_GPU_CLOCK_COUNT(GC domain) register access. :-) We don't support enable/disable gfxoff feature dynamically yet. Yes, this is the next step that I should try to do it. With the issue is resolved, I think we can provide an interface as you can configure it in the power profile. Before that, can we return "0" at gfx_v9_0_get_gpu_clock_counter when gfx is in off in order to bypass RLC_GPU_CLOCK_COUNT registers? Thanks, Ray
