Messages in this thread | | | Subject | Re: [PATCH v10 3/4] drm/panfrost: devfreq: Disable devfreq when num_supplies > 1 | From | Steven Price <> | Date | Thu, 14 Jan 2021 15:10:25 +0000 |
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On 13/01/2021 06:07, Nicolas Boichat wrote: > GPUs with more than a single regulator (e.g. G72 on MT8183) will > require platform-specific handling for devfreq, for 2 reasons: > 1. The opp core (drivers/opp/core.c:_generic_set_opp_regulator) > does not support multiple regulators, so we'll need custom > handlers. > 2. Generally, platforms with 2 regulators have platform-specific > constraints on how the voltages should be set (e.g. > minimum/maximum voltage difference between them), so we > should not just create generic handlers that simply > change the voltages without taking care of those constraints. > > Disable devfreq for now on those GPUs. > > Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> > Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Thanks for the clarification in the commit message.
Reviewed-by: Steven Price <steven.price@arm.com>
> --- > > (no changes since v9) > > Changes in v9: > - Explain why devfreq needs to be disabled for GPUs with >1 > regulators. > > Changes in v8: > - Use DRM_DEV_INFO instead of ERROR > > Changes in v7: > - Fix GPU ID in commit message > > 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..812cfecdee3b 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_INFO(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)) { >
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