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SubjectRe: [PATCH 3/4] drm/panfrost: Implement ability to turn on/off regulators in suspend
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Il 30/10/23 15:57, Steven Price ha scritto:
> On 30/10/2023 13:22, AngeloGioacchino Del Regno wrote:
>> Some platforms/SoCs can power off the GPU entirely by completely cutting
>> off power, greatly enhancing battery time during system suspend: add a
>> new pm_feature GPU_PM_VREG_OFF to allow turning off the GPU regulators
>> during full suspend only on selected platforms.
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>> ---
>> drivers/gpu/drm/panfrost/panfrost_device.c | 19 ++++++++++++++++++-
>> drivers/gpu/drm/panfrost/panfrost_device.h | 2 ++
>> 2 files changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
>> index 2022ed76a620..51b22eb0971d 100644
>> --- a/drivers/gpu/drm/panfrost/panfrost_device.c
>> +++ b/drivers/gpu/drm/panfrost/panfrost_device.c
>> @@ -431,10 +431,21 @@ static int panfrost_device_resume(struct device *dev)
>> struct panfrost_device *pfdev = dev_get_drvdata(dev);
>> int ret;
>>
>> + if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF)) {
>> + unsigned long freq = pfdev->pfdevfreq.fast_rate;
>> + struct dev_pm_opp *opp;
>> +
>> + opp = dev_pm_opp_find_freq_ceil(dev, &freq);
>> + if (IS_ERR(opp))
>> + return PTR_ERR(opp);
>> + dev_pm_opp_put(opp);
>> + dev_pm_opp_set_opp(dev, opp);
>
> These lines look the wrong way round - surely we want to hang onto the
> reference until the set_opp call is made?
>

Whoops! Yes, thanks, this happened during a cleanup for whatever reason.
I'll invert those for v2.

Angelo

> Steve
>
>> + }
>> +
>> if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS)) {
>> ret = clk_enable(pfdev->clock);
>> if (ret)
>> - return ret;
>> + goto err_clk;
>>
>> if (pfdev->bus_clock) {
>> ret = clk_enable(pfdev->bus_clock);
>> @@ -455,6 +466,9 @@ static int panfrost_device_resume(struct device *dev)
>> err_bus_clk:
>> if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS))
>> clk_disable(pfdev->clock);
>> +err_clk:
>> + if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF))
>> + dev_pm_opp_set_opp(dev, NULL);
>> return ret;
>> }
>>
>> @@ -474,6 +488,9 @@ static int panfrost_device_suspend(struct device *dev)
>> clk_disable(pfdev->bus_clock);
>> }
>>
>> + if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF))
>> + dev_pm_opp_set_opp(dev, NULL);
>> +
>> return 0;
>> }
>>
>> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
>> index d7f179eb8ea3..0fc558db6bfd 100644
>> --- a/drivers/gpu/drm/panfrost/panfrost_device.h
>> +++ b/drivers/gpu/drm/panfrost/panfrost_device.h
>> @@ -28,9 +28,11 @@ struct panfrost_perfcnt;
>> /**
>> * enum panfrost_gpu_pm - Supported kernel power management features
>> * @GPU_PM_CLK_DIS: Allow disabling clocks during system suspend
>> + * @GPU_PM_VREG_OFF: Allow turning off regulators during system suspend
>> */
>> enum panfrost_gpu_pm {
>> GPU_PM_CLK_DIS,
>> + GPU_PM_VREG_OFF,
>> };
>>
>> struct panfrost_features {
>
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