* Re: [PATCH] PCI: For d3_delay and d3cold_delay, zero means zero
2017-03-14 13:21 ` Adrian Hunter
@ 2017-03-14 13:23 ` Adrian Hunter
2017-03-14 17:52 ` Rafael J. Wysocki
2017-03-14 20:04 ` Bjorn Helgaas
2 siblings, 0 replies; 6+ messages in thread
From: Adrian Hunter @ 2017-03-14 13:23 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: linux-pci, linux-pm, linux-acpi, Rafael J. Wysocki, Lukas Wunner,
Andy Shevchenko, Mika Westerberg
Forgot to put this is V2, sorry. It has changes to the commit message as
requested.
On 14/03/17 15:21, Adrian Hunter wrote:
> msleep() still sleeps 1 jiffy even when told to sleep for zero
> milliseconds. That can end up being 1-2 milliseconds or more. In the cases
> of d3_delay and d3cold_delay, that unnecessarily increases suspend and/or
> resume latencies.
>
> So, do not sleep at all for the respective cases of d3_delay is zero or
> d3cold_delay is zero.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
> drivers/pci/pci.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7904d02ffdb9..9779483f81fd 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -66,7 +66,8 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
> if (delay < pci_pm_d3_delay)
> delay = pci_pm_d3_delay;
>
> - msleep(delay);
> + if (delay)
> + msleep(delay);
> }
>
> #ifdef CONFIG_PCI_DOMAINS
> @@ -827,7 +828,8 @@ static void __pci_start_power_transition(struct pci_dev *dev, pci_power_t state)
> * because have already delayed for the bridge.
> */
> if (dev->runtime_d3cold) {
> - msleep(dev->d3cold_delay);
> + if (dev->d3cold_delay)
> + msleep(dev->d3cold_delay);
> /*
> * When powering on a bridge from D3cold, the
> * whole hierarchy may be powered on into
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] PCI: For d3_delay and d3cold_delay, zero means zero
2017-03-14 13:21 ` Adrian Hunter
2017-03-14 13:23 ` Adrian Hunter
@ 2017-03-14 17:52 ` Rafael J. Wysocki
2017-03-14 20:04 ` Bjorn Helgaas
2 siblings, 0 replies; 6+ messages in thread
From: Rafael J. Wysocki @ 2017-03-14 17:52 UTC (permalink / raw)
To: Adrian Hunter
Cc: Bjorn Helgaas, linux-pci, linux-pm, linux-acpi,
Rafael J. Wysocki, Lukas Wunner, Andy Shevchenko,
Mika Westerberg
On Tue, Mar 14, 2017 at 2:21 PM, Adrian Hunter <adrian.hunter@intel.com> wrote:
> msleep() still sleeps 1 jiffy even when told to sleep for zero
> milliseconds. That can end up being 1-2 milliseconds or more. In the cases
> of d3_delay and d3cold_delay, that unnecessarily increases suspend and/or
> resume latencies.
>
> So, do not sleep at all for the respective cases of d3_delay is zero or
> d3cold_delay is zero.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/pci/pci.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7904d02ffdb9..9779483f81fd 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -66,7 +66,8 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
> if (delay < pci_pm_d3_delay)
> delay = pci_pm_d3_delay;
>
> - msleep(delay);
> + if (delay)
> + msleep(delay);
> }
>
> #ifdef CONFIG_PCI_DOMAINS
> @@ -827,7 +828,8 @@ static void __pci_start_power_transition(struct pci_dev *dev, pci_power_t state)
> * because have already delayed for the bridge.
> */
> if (dev->runtime_d3cold) {
> - msleep(dev->d3cold_delay);
> + if (dev->d3cold_delay)
> + msleep(dev->d3cold_delay);
> /*
> * When powering on a bridge from D3cold, the
> * whole hierarchy may be powered on into
> --
> 1.9.1
>
> --
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] PCI: For d3_delay and d3cold_delay, zero means zero
2017-03-14 13:21 ` Adrian Hunter
2017-03-14 13:23 ` Adrian Hunter
2017-03-14 17:52 ` Rafael J. Wysocki
@ 2017-03-14 20:04 ` Bjorn Helgaas
2 siblings, 0 replies; 6+ messages in thread
From: Bjorn Helgaas @ 2017-03-14 20:04 UTC (permalink / raw)
To: Adrian Hunter
Cc: linux-pci, linux-pm, linux-acpi, Rafael J. Wysocki, Lukas Wunner,
Andy Shevchenko, Mika Westerberg
On Tue, Mar 14, 2017 at 03:21:58PM +0200, Adrian Hunter wrote:
> msleep() still sleeps 1 jiffy even when told to sleep for zero
> milliseconds. That can end up being 1-2 milliseconds or more. In the cases
> of d3_delay and d3cold_delay, that unnecessarily increases suspend and/or
> resume latencies.
>
> So, do not sleep at all for the respective cases of d3_delay is zero or
> d3cold_delay is zero.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Applied with Rafael's ack to pci/pm for v4.12, thanks!
> ---
> drivers/pci/pci.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7904d02ffdb9..9779483f81fd 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -66,7 +66,8 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
> if (delay < pci_pm_d3_delay)
> delay = pci_pm_d3_delay;
>
> - msleep(delay);
> + if (delay)
> + msleep(delay);
> }
>
> #ifdef CONFIG_PCI_DOMAINS
> @@ -827,7 +828,8 @@ static void __pci_start_power_transition(struct pci_dev *dev, pci_power_t state)
> * because have already delayed for the bridge.
> */
> if (dev->runtime_d3cold) {
> - msleep(dev->d3cold_delay);
> + if (dev->d3cold_delay)
> + msleep(dev->d3cold_delay);
> /*
> * When powering on a bridge from D3cold, the
> * whole hierarchy may be powered on into
> --
> 1.9.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread