* Re: [PATCH v2 1/2] PCI/PM: refactor pci_pm_suspend_noirq()
[not found] <20220317233153.2617938-1-rajvi.jingar@intel.com>
@ 2022-03-18 2:09 ` David E. Box
2022-03-18 19:41 ` Rafael J. Wysocki
[not found] ` <20220317233153.2617938-2-rajvi.jingar@intel.com>
2 siblings, 0 replies; 3+ messages in thread
From: David E. Box @ 2022-03-18 2:09 UTC (permalink / raw)
To: Rajvi Jingar, rafael.j.wysocki, bhelgaas
Cc: linux-pci, linux-kernel, linux-pm
Hi Rajvi,
On Thu, 2022-03-17 at 16:31 -0700, Rajvi Jingar wrote:
> The state of the device is saved during pci_pm_suspend_noirq(), if it
> has not already been saved, regardless of the skip_bus_pm flag value. So
> skip_bus_pm check is removed before saving the device state.
>
> v2: add comments to the changes
...
>
> Signed-off-by: Rajvi Jingar <rajvi.jingar@intel.com>
> Suggested-by: David E. Box <david.e.box@linux.intel.com>
> ---
Patch changelogs aren't kept in the commit message. Place them here after the
"---" line. In this location, it won't affect applying the patch.
David
> drivers/pci/pci-driver.c | 18 ++++++------------
> 1 file changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 588588cfda48..ffe76f238d7e 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -834,20 +834,14 @@ static int pci_pm_suspend_noirq(struct device *dev)
> }
> }
>
> - if (pci_dev->skip_bus_pm) {
> + if (!pci_dev->state_saved) {
> + pci_save_state(pci_dev);
> /*
> - * Either the device is a bridge with a child in D0 below it, or
> - * the function is running for the second time in a row without
> - * going through full resume, which is possible only during
> - * suspend-to-idle in a spurious wakeup case. The device should
> - * be in D0 at this point, but if it is a bridge, it may be
> - * necessary to save its state.
> + * If the device is a bridge with a child in D0 below it, it
> needs to
> + * stay in D0, so check skip_bus_pm to avoid putting it into a
> + * low-power state in that case.
> */
> - if (!pci_dev->state_saved)
> - pci_save_state(pci_dev);
> - } else if (!pci_dev->state_saved) {
> - pci_save_state(pci_dev);
> - if (pci_power_manageable(pci_dev))
> + if (!pci_dev->skip_bus_pm && pci_power_manageable(pci_dev))
> pci_prepare_to_sleep(pci_dev);
> }
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2 1/2] PCI/PM: refactor pci_pm_suspend_noirq()
[not found] <20220317233153.2617938-1-rajvi.jingar@intel.com>
2022-03-18 2:09 ` [PATCH v2 1/2] PCI/PM: refactor pci_pm_suspend_noirq() David E. Box
@ 2022-03-18 19:41 ` Rafael J. Wysocki
[not found] ` <20220317233153.2617938-2-rajvi.jingar@intel.com>
2 siblings, 0 replies; 3+ messages in thread
From: Rafael J. Wysocki @ 2022-03-18 19:41 UTC (permalink / raw)
To: Rajvi Jingar, bhelgaas; +Cc: david.e.box, linux-pci, linux-kernel, linux-pm
On 3/18/2022 12:31 AM, Rajvi Jingar wrote:
> The state of the device is saved during pci_pm_suspend_noirq(), if it
> has not already been saved, regardless of the skip_bus_pm flag value. So
> skip_bus_pm check is removed before saving the device state.
>
> v2: add comments to the changes
As mentioned by Dave, this shouldn't be here.
> Signed-off-by: Rajvi Jingar <rajvi.jingar@intel.com>
> Suggested-by: David E. Box <david.e.box@linux.intel.com>
> ---
> drivers/pci/pci-driver.c | 18 ++++++------------
> 1 file changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 588588cfda48..ffe76f238d7e 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -834,20 +834,14 @@ static int pci_pm_suspend_noirq(struct device *dev)
> }
> }
>
> - if (pci_dev->skip_bus_pm) {
> + if (!pci_dev->state_saved) {
> + pci_save_state(pci_dev);
> /*
> - * Either the device is a bridge with a child in D0 below it, or
> - * the function is running for the second time in a row without
> - * going through full resume, which is possible only during
> - * suspend-to-idle in a spurious wakeup case. The device should
> - * be in D0 at this point, but if it is a bridge, it may be
> - * necessary to save its state.
> + * If the device is a bridge with a child in D0 below it, it needs to
> + * stay in D0, so check skip_bus_pm to avoid putting it into a
> + * low-power state in that case.
> */
> - if (!pci_dev->state_saved)
> - pci_save_state(pci_dev);
> - } else if (!pci_dev->state_saved) {
> - pci_save_state(pci_dev);
> - if (pci_power_manageable(pci_dev))
> + if (!pci_dev->skip_bus_pm && pci_power_manageable(pci_dev))
> pci_prepare_to_sleep(pci_dev);
> }
>
^ permalink raw reply [flat|nested] 3+ messages in thread[parent not found: <20220317233153.2617938-2-rajvi.jingar@intel.com>]
* Re: [PATCH v2 2/2] PCI/PM: Fix pci_pm_suspend_noirq() to disable PTM
[not found] ` <20220317233153.2617938-2-rajvi.jingar@intel.com>
@ 2022-03-18 19:42 ` Rafael J. Wysocki
0 siblings, 0 replies; 3+ messages in thread
From: Rafael J. Wysocki @ 2022-03-18 19:42 UTC (permalink / raw)
To: Rajvi Jingar, bhelgaas; +Cc: david.e.box, linux-pci, linux-kernel, linux-pm
On 3/18/2022 12:31 AM, Rajvi Jingar wrote:
> For the PCIe devices (like nvme) that do not go into D3 state still need to
> disable PTM on PCIe root ports to allow the port to enter a lower-power PM
> state and the SoC to reach a lower-power idle state as a whole. Move the
> pci_disable_ptm() out of pci_prepare_to_sleep() as this code path is not
> followed for devices that do not go into D3. This patch fixes the issue
> seen on Dell XPS 9300 with Ice Lake CPU and Dell Precision 5530 with Coffee
> Lake CPU platforms to get improved residency in low power idle states.
>
> v2: add Fixes tag in commit message
Again, please move the above line after the tags below and add another
--- marker between it and the tags.
> Fixes: a697f072f5da ("PCI: Disable PTM during suspend to save power")
> Signed-off-by: Rajvi Jingar <rajvi.jingar@intel.com>
> Suggested-by: David E. Box <david.e.box@linux.intel.com>
> ---
> drivers/pci/pci-driver.c | 10 ++++++++++
> drivers/pci/pci.c | 10 ----------
> 2 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index ffe76f238d7e..228d21700825 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -836,6 +836,16 @@ static int pci_pm_suspend_noirq(struct device *dev)
>
> if (!pci_dev->state_saved) {
> pci_save_state(pci_dev);
> + /*
> + * There are systems (for example, Intel mobile chips since Coffee
> + * Lake) where the power drawn while suspended can be significantly
> + * reduced by disabling PTM on PCIe root ports as this allows the
> + * port to enter a lower-power PM state and the SoC to reach a
> + * lower-power idle state as a whole.
> + */
> + if (pci_pcie_type(pci_dev) == PCI_EXP_TYPE_ROOT_PORT)
> + pci_disable_ptm(pci_dev);
> +
> /*
> * If the device is a bridge with a child in D0 below it, it needs to
> * stay in D0, so check skip_bus_pm to avoid putting it into a
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 9ecce435fb3f..f8768672c064 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2660,16 +2660,6 @@ int pci_prepare_to_sleep(struct pci_dev *dev)
> if (target_state == PCI_POWER_ERROR)
> return -EIO;
>
> - /*
> - * There are systems (for example, Intel mobile chips since Coffee
> - * Lake) where the power drawn while suspended can be significantly
> - * reduced by disabling PTM on PCIe root ports as this allows the
> - * port to enter a lower-power PM state and the SoC to reach a
> - * lower-power idle state as a whole.
> - */
> - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
> - pci_disable_ptm(dev);
> -
> pci_enable_wake(dev, target_state, wakeup);
>
> error = pci_set_power_state(dev, target_state);
^ permalink raw reply [flat|nested] 3+ messages in thread