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Groups > linux.kernel > #1292500 > unrolled thread
| Started by | Ulf Hansson <ulf.hansson@linaro.org> |
|---|---|
| First post | 2015-12-15 21:00 +0100 |
| Last post | 2015-12-16 14:00 +0100 |
| Articles | 5 — 2 participants |
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Re: [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS Ulf Hansson <ulf.hansson@linaro.org> - 2015-12-15 21:00 +0100
Re: [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS Jon Hunter <jonathanh@nvidia.com> - 2015-12-16 10:50 +0100
Re: [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS Ulf Hansson <ulf.hansson@linaro.org> - 2015-12-16 10:50 +0100
Re: [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS Jon Hunter <jonathanh@nvidia.com> - 2015-12-16 12:50 +0100
Re: [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS Ulf Hansson <ulf.hansson@linaro.org> - 2015-12-16 14:00 +0100
| From | Ulf Hansson <ulf.hansson@linaro.org> |
|---|---|
| Date | 2015-12-15 21:00 +0100 |
| Subject | Re: [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS |
| Message-ID | <qG3Vo-aC-19@gated-at.bofh.it> |
On 4 December 2015 at 15:57, Jon Hunter <jonathanh@nvidia.com> wrote: > Enable PM_GENERIC_DOMAINS for tegra 64-bit devices. To ensure that devices > dependent upon a particular power-domain are only probed when that power > domain has been powered up, requires that PM is made mandatory for tegra > 64-bit devices and so select this option for tegra as well. > > Signed-off-by: Jon Hunter <jonathanh@nvidia.com> > --- > arch/arm64/Kconfig.platforms | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms > index 9806324fa215..e0b5bd0aff0f 100644 > --- a/arch/arm64/Kconfig.platforms > +++ b/arch/arm64/Kconfig.platforms > @@ -93,6 +93,8 @@ config ARCH_TEGRA > select GENERIC_CLOCKEVENTS > select HAVE_CLK > select PINCTRL > + select PM > + select PM_GENERIC_DOMAINS If you still want to allow ARCH_TEGRA to run without PM, you should probably change to: select PM_GENERIC_DOMAINS if PM > select RESET_CONTROLLER > help > This enables support for the NVIDIA Tegra SoC family. > -- > 2.1.4 > Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Jon Hunter <jonathanh@nvidia.com> |
|---|---|
| Date | 2015-12-16 10:50 +0100 |
| Message-ID | <qGgSB-8tQ-1@gated-at.bofh.it> |
| In reply to | #1292500 |
Hi Ulf, On 15/12/15 19:54, Ulf Hansson wrote: > On 4 December 2015 at 15:57, Jon Hunter <jonathanh@nvidia.com> wrote: >> Enable PM_GENERIC_DOMAINS for tegra 64-bit devices. To ensure that devices >> dependent upon a particular power-domain are only probed when that power >> domain has been powered up, requires that PM is made mandatory for tegra >> 64-bit devices and so select this option for tegra as well. >> >> Signed-off-by: Jon Hunter <jonathanh@nvidia.com> >> --- >> arch/arm64/Kconfig.platforms | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms >> index 9806324fa215..e0b5bd0aff0f 100644 >> --- a/arch/arm64/Kconfig.platforms >> +++ b/arch/arm64/Kconfig.platforms >> @@ -93,6 +93,8 @@ config ARCH_TEGRA >> select GENERIC_CLOCKEVENTS >> select HAVE_CLK >> select PINCTRL >> + select PM >> + select PM_GENERIC_DOMAINS > > If you still want to allow ARCH_TEGRA to run without PM, you should > probably change to: > > select PM_GENERIC_DOMAINS if PM Per the changelog this is deliberate. If we allow !PM, then there is a potential that you could probe a device when the power domain is not powered on. I understand that some SoCs turn on all the power-domains when !PM but this will not work for tegra because we don't register the power domain until later in the boot and so we are relying upon probe deferral to defer the probe of devices that use power-domains. Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Ulf Hansson <ulf.hansson@linaro.org> |
|---|---|
| Date | 2015-12-16 10:50 +0100 |
| Message-ID | <qGgSB-8tQ-9@gated-at.bofh.it> |
| In reply to | #1292848 |
On 16 December 2015 at 10:40, Jon Hunter <jonathanh@nvidia.com> wrote: > Hi Ulf, > > On 15/12/15 19:54, Ulf Hansson wrote: >> On 4 December 2015 at 15:57, Jon Hunter <jonathanh@nvidia.com> wrote: >>> Enable PM_GENERIC_DOMAINS for tegra 64-bit devices. To ensure that devices >>> dependent upon a particular power-domain are only probed when that power >>> domain has been powered up, requires that PM is made mandatory for tegra >>> 64-bit devices and so select this option for tegra as well. >>> >>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com> >>> --- >>> arch/arm64/Kconfig.platforms | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms >>> index 9806324fa215..e0b5bd0aff0f 100644 >>> --- a/arch/arm64/Kconfig.platforms >>> +++ b/arch/arm64/Kconfig.platforms >>> @@ -93,6 +93,8 @@ config ARCH_TEGRA >>> select GENERIC_CLOCKEVENTS >>> select HAVE_CLK >>> select PINCTRL >>> + select PM >>> + select PM_GENERIC_DOMAINS >> >> If you still want to allow ARCH_TEGRA to run without PM, you should >> probably change to: >> >> select PM_GENERIC_DOMAINS if PM > > Per the changelog this is deliberate. If we allow !PM, then there is a > potential that you could probe a device when the power domain is not > powered on. I understand that some SoCs turn on all the power-domains > when !PM but this will not work for tegra because we don't register the > power domain until later in the boot and so we are relying upon probe > deferral to defer the probe of devices that use power-domains. So what you are saying is that adding the PM domain support, will fix some devices to become successfully probed as they were broken before? If that's the case, this makes all good sense! Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Jon Hunter <jonathanh@nvidia.com> |
|---|---|
| Date | 2015-12-16 12:50 +0100 |
| Message-ID | <qGiKK-1es-25@gated-at.bofh.it> |
| In reply to | #1292851 |
On 16/12/15 09:47, Ulf Hansson wrote: > On 16 December 2015 at 10:40, Jon Hunter <jonathanh@nvidia.com> wrote: >> Hi Ulf, >> >> On 15/12/15 19:54, Ulf Hansson wrote: >>> On 4 December 2015 at 15:57, Jon Hunter <jonathanh@nvidia.com> wrote: >>>> Enable PM_GENERIC_DOMAINS for tegra 64-bit devices. To ensure that devices >>>> dependent upon a particular power-domain are only probed when that power >>>> domain has been powered up, requires that PM is made mandatory for tegra >>>> 64-bit devices and so select this option for tegra as well. >>>> >>>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com> >>>> --- >>>> arch/arm64/Kconfig.platforms | 2 ++ >>>> 1 file changed, 2 insertions(+) >>>> >>>> diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms >>>> index 9806324fa215..e0b5bd0aff0f 100644 >>>> --- a/arch/arm64/Kconfig.platforms >>>> +++ b/arch/arm64/Kconfig.platforms >>>> @@ -93,6 +93,8 @@ config ARCH_TEGRA >>>> select GENERIC_CLOCKEVENTS >>>> select HAVE_CLK >>>> select PINCTRL >>>> + select PM >>>> + select PM_GENERIC_DOMAINS >>> >>> If you still want to allow ARCH_TEGRA to run without PM, you should >>> probably change to: >>> >>> select PM_GENERIC_DOMAINS if PM >> >> Per the changelog this is deliberate. If we allow !PM, then there is a >> potential that you could probe a device when the power domain is not >> powered on. I understand that some SoCs turn on all the power-domains >> when !PM but this will not work for tegra because we don't register the >> power domain until later in the boot and so we are relying upon probe >> deferral to defer the probe of devices that use power-domains. > > So what you are saying is that adding the PM domain support, will fix > some devices to become successfully probed as they were broken before? Not exactly. There is a legacy tegra_powergate_sequence_power_up() that has been used to date to get around this. However, by migrating to GENPD we really need to make PM mandatory, otherwise you could attempt to probe a device in a power domain that is not powered. In other words, you are probing blindly. I know some SoCs do this, but that does not seem very robust. Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Ulf Hansson <ulf.hansson@linaro.org> |
|---|---|
| Date | 2015-12-16 14:00 +0100 |
| Message-ID | <qGjQu-1SH-11@gated-at.bofh.it> |
| In reply to | #1292919 |
On 16 December 2015 at 12:40, Jon Hunter <jonathanh@nvidia.com> wrote: > > On 16/12/15 09:47, Ulf Hansson wrote: >> On 16 December 2015 at 10:40, Jon Hunter <jonathanh@nvidia.com> wrote: >>> Hi Ulf, >>> >>> On 15/12/15 19:54, Ulf Hansson wrote: >>>> On 4 December 2015 at 15:57, Jon Hunter <jonathanh@nvidia.com> wrote: >>>>> Enable PM_GENERIC_DOMAINS for tegra 64-bit devices. To ensure that devices >>>>> dependent upon a particular power-domain are only probed when that power >>>>> domain has been powered up, requires that PM is made mandatory for tegra >>>>> 64-bit devices and so select this option for tegra as well. >>>>> >>>>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com> >>>>> --- >>>>> arch/arm64/Kconfig.platforms | 2 ++ >>>>> 1 file changed, 2 insertions(+) >>>>> >>>>> diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms >>>>> index 9806324fa215..e0b5bd0aff0f 100644 >>>>> --- a/arch/arm64/Kconfig.platforms >>>>> +++ b/arch/arm64/Kconfig.platforms >>>>> @@ -93,6 +93,8 @@ config ARCH_TEGRA >>>>> select GENERIC_CLOCKEVENTS >>>>> select HAVE_CLK >>>>> select PINCTRL >>>>> + select PM >>>>> + select PM_GENERIC_DOMAINS >>>> >>>> If you still want to allow ARCH_TEGRA to run without PM, you should >>>> probably change to: >>>> >>>> select PM_GENERIC_DOMAINS if PM >>> >>> Per the changelog this is deliberate. If we allow !PM, then there is a >>> potential that you could probe a device when the power domain is not >>> powered on. I understand that some SoCs turn on all the power-domains >>> when !PM but this will not work for tegra because we don't register the >>> power domain until later in the boot and so we are relying upon probe >>> deferral to defer the probe of devices that use power-domains. >> >> So what you are saying is that adding the PM domain support, will fix >> some devices to become successfully probed as they were broken before? > > Not exactly. There is a legacy tegra_powergate_sequence_power_up() that > has been used to date to get around this. However, by migrating to GENPD > we really need to make PM mandatory, otherwise you could attempt to > probe a device in a power domain that is not powered. In other words, > you are probing blindly. I know some SoCs do this, but that does not > seem very robust. Thank for the clarification. I agree. You may add my: Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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