Messages in this thread | | | Date | Sat, 18 Feb 2023 18:47:44 +0200 | Subject | Re: [PATCH v2 06/14] drm/msm/gpu: Use dev_pm_opp_set_rate for non-GMU GPUs | From | Dmitry Baryshkov <> |
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On 18/02/2023 13:04, Konrad Dybcio wrote: > > > On 17.02.2023 22:07, Dmitry Baryshkov wrote: >> On 14/02/2023 19:31, Konrad Dybcio wrote: >>> Currently we only utilize the OPP table connected to the GPU for >>> getting (available) frequencies. We do however need to scale the >>> voltage rail(s) accordingly to ensure that we aren't trying to >>> run the GPU at 1GHz with a VDD_LOW vote, as that would result in >>> an otherwise inexplainable hang. >>> >>> Tell the OPP framework that we want to scale the "core" clock >>> and swap out the clk_set_rate to a dev_pm_opp_set_rate in >>> msm_devfreq_target() to enable usage of required-opps and by >>> extension proper voltage level/corner scaling. >>> >>> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org> >>> --- >>> drivers/gpu/drm/msm/adreno/adreno_gpu.c | 4 ++++ >>> drivers/gpu/drm/msm/msm_gpu_devfreq.c | 2 +- >>> 2 files changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c >>> index ce6b76c45b6f..15e405e4f977 100644 >>> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c >>> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c >>> @@ -1047,6 +1047,10 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev, >>> const char *gpu_name; >>> u32 speedbin; >>> + /* This can only be done here, or devm_pm_opp_set_supported_hw will WARN_ON() */ >>> + if (!IS_ERR(devm_clk_get(dev, "core"))) >>> + devm_pm_opp_set_clkname(dev, "core"); >> >> Can we instead move a call to a6xx_set_supported_hw() / check_speed_bin after the adreno_gpu_init() ? It will call msm_gpu_init, which in turn sets gpu->core_clk. >> >> Ideally you can call devm_pm_opp_set_clkname() from that function. > > >> Or maybe completely drop gpu->core_clk and always use devm_pm_opp_set_clk_rate(). > That would break non-OPP targets, last of which were probably added N=big years ago..
No. In the lack of OPP tables, dev_pm_opp_clk_set_rate() should behave exactly like the clk_set_rate().
> I'm not sure these would still work, as I think we've got rid of some ugly > clock getters that were looking for both "core" and "core_clk" etc.
We still support core vs core_clk, see the get_clocks() at msm_gpu.c and then msm_clk_bulk_get_clock(). However we might mimick this function and call devm_pm_opp_set_clkname() with the proper name ("core" or "core_clk").
> > See 8db0b6c7b636376789e356d861c3c6c35dcb6913 for what seems to be the most recent > example of non-OPP. > > IMX51/53 also have no OPP tables and are using the (AFAIK) now-defunct _clk-suffixed > clock-names.
It works, I tested it during this cycle.
> > I'd be more than happy to rip out some of this legacy code and convert it > to something modern like OPP, but I'm not sure you guys would like it considering > the breakage on (arguably ancient and borderline retired) platforms.
I think, we should try switching to OPP-for-everybody, granted the promise of dev_pm_opp_set_clk_rate() being backwards compatible with bare clk_set_rate().
> > This patch as-is "only" breaks non-OPP a5xx & a6xx (as they have .gpu_busy defined), > of which there are none.. > >> >>> + >>> adreno_gpu->funcs = funcs; >>> adreno_gpu->info = adreno_info(config->rev); >>> adreno_gpu->gmem = adreno_gpu->info->gmem; >>> diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c >>> index e27dbf12b5e8..ea70c1c32d94 100644 >>> --- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c >>> +++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c >>> @@ -48,7 +48,7 @@ static int msm_devfreq_target(struct device *dev, unsigned long *freq, >>> gpu->funcs->gpu_set_freq(gpu, opp, df->suspended); >>> mutex_unlock(&df->lock); >>> } else { >>> - clk_set_rate(gpu->core_clk, *freq); >>> + dev_pm_opp_set_rate(dev, *freq); >> >> This is not enough, there are calls to clk_set_rate(gpu->core_clk) in msm_gpu.c which are called from the suspend/resume path. > Right, good catch. > > Konrad >> >>> } >>> dev_pm_opp_put(opp); >>
-- With best wishes Dmitry
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