On Thu, Jan 7, 2021 at 11:59 PM Steven Price <steven.price@xxxxxxx> wrote: > > On 05/01/2021 00:11, Nicolas Boichat wrote: > > GPUs with more than a single regulator (e.g. G-57 on MT8183) will > > require platform-specific handling, disable devfreq for now. > > Can you explain what actually goes wrong here? AFAICT the existing code > does support controlling multiple regulators - but clearly this is the > first platform that exercises that code with num_supplies>1. Sure, I should have expanded in the commit message, will do in v9. We have support for >1 supplies, and we need to enable them to get the GPU running _at all_ (and the default voltages should be safe by design). For devfreq though: 1. There are constraints on the voltage difference between the core and SRAM, we have this caterpillar logic downstream [1], so somebody will need to port it (TBH I don't think it's overly critical at this point, as Bifrost support is still not very mature from what I can see, and devfreq is purely a performance thing). 2. The core [2] does not support multiple regulators, so we'll need custom code anyway. Even if we didn't have constraints. [1] https://chromium.googlesource.com/chromiumos/third_party/kernel/+/refs/heads/chromeos-4.19/drivers/gpu/arm/bifrost/platform/mediatek/mali_kbase_runtime_pm.c#367 [2] https://elixir.bootlin.com/linux/latest/source/drivers/opp/core.c#L679 > > Steve > > > > > Signed-off-by: Nicolas Boichat <drinkcat@xxxxxxxxxxxx> > > --- > > > > Changes in v6: > > - New change > > > > drivers/gpu/drm/panfrost/panfrost_devfreq.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c b/drivers/gpu/drm/panfrost/panfrost_devfreq.c > > index f44d28fad085..1f49043aae73 100644 > > --- a/drivers/gpu/drm/panfrost/panfrost_devfreq.c > > +++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.c > > @@ -92,6 +92,15 @@ int panfrost_devfreq_init(struct panfrost_device *pfdev) > > struct thermal_cooling_device *cooling; > > struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq; > > > > + if (pfdev->comp->num_supplies > 1) { > > + /* > > + * GPUs with more than 1 supply require platform-specific handling: > > + * continue without devfreq > > + */ > > + DRM_DEV_ERROR(dev, "More than 1 supply is not supported yet\n"); > > + return 0; > > + } > > + > > opp_table = dev_pm_opp_set_regulators(dev, pfdev->comp->supply_names, > > pfdev->comp->num_supplies); > > if (IS_ERR(opp_table)) { > > > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
