From: Bjorn Helgaas <helgaas@kernel.org>
To: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: m.chetan.kumar@intel.com, linuxwwan@intel.com,
linux-pci@vger.kernel.org, linux-pm@vger.kernel.org,
Loic Poulain <loic.poulain@linaro.org>,
Sergey Ryazanov <ryazanov.s.a@gmail.com>,
Johannes Berg <johannes@sipsolutions.net>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Vaibhav Gupta <vaibhavgupta40@gmail.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>
Subject: Re: [PATCH 1/2] net: wwan: iosm: Let PCI core handle PCI power transition
Date: Wed, 29 Dec 2021 14:12:29 -0600 [thread overview]
Message-ID: <20211229201229.GA1698801@bhelgaas> (raw)
In-Reply-To: <20211224081914.345292-1-kai.heng.feng@canonical.com>
[+cc Rafael, in case you have insight about the PCI_D0 question below;
Vaibhav, since this is related to your generic PM conversions]
On Fri, Dec 24, 2021 at 04:19:13PM +0800, Kai-Heng Feng wrote:
> pci_pm_suspend_noirq() and pci_pm_resume_noirq() already handle power
> transition for system-wide suspend and resume, so it's not necessary to
> do it in the driver.
I see DaveM has already applied this, but it looks good to me, thanks
for doing this!
One minor question below...
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
> drivers/net/wwan/iosm/iosm_ipc_pcie.c | 49 ++-------------------------
> 1 file changed, 2 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/net/wwan/iosm/iosm_ipc_pcie.c b/drivers/net/wwan/iosm/iosm_ipc_pcie.c
> index 2fe88b8be3481..d73894e2a84ed 100644
> --- a/drivers/net/wwan/iosm/iosm_ipc_pcie.c
> +++ b/drivers/net/wwan/iosm/iosm_ipc_pcie.c
> @@ -363,67 +363,22 @@ static int __maybe_unused ipc_pcie_resume_s2idle(struct iosm_pcie *ipc_pcie)
>
> int __maybe_unused ipc_pcie_suspend(struct iosm_pcie *ipc_pcie)
> {
> - struct pci_dev *pdev;
> - int ret;
> -
> - pdev = ipc_pcie->pci;
> -
> - /* Execute D3 one time. */
> - if (pdev->current_state != PCI_D0) {
> - dev_dbg(ipc_pcie->dev, "done for PM=%d", pdev->current_state);
> - return 0;
> - }
I don't understand the intent of this early exit, and it's not obvious
to me that pci_pm_suspend_noirq() bails out early when
(pdev->current_state != PCI_D0).
> /* The HAL shall ask the shared memory layer whether D3 is allowed. */
> ipc_imem_pm_suspend(ipc_pcie->imem);
>
> - /* Save the PCI configuration space of a device before suspending. */
> - ret = pci_save_state(pdev);
> -
> - if (ret) {
> - dev_err(ipc_pcie->dev, "pci_save_state error=%d", ret);
> - return ret;
> - }
> -
> - /* Set the power state of a PCI device.
> - * Transition a device to a new power state, using the device's PCI PM
> - * registers.
> - */
> - ret = pci_set_power_state(pdev, PCI_D3cold);
> -
> - if (ret) {
> - dev_err(ipc_pcie->dev, "pci_set_power_state error=%d", ret);
> - return ret;
> - }
> -
> dev_dbg(ipc_pcie->dev, "SUSPEND done");
> - return ret;
> + return 0;
> }
>
> int __maybe_unused ipc_pcie_resume(struct iosm_pcie *ipc_pcie)
> {
> - int ret;
> -
> - /* Set the power state of a PCI device.
> - * Transition a device to a new power state, using the device's PCI PM
> - * registers.
> - */
> - ret = pci_set_power_state(ipc_pcie->pci, PCI_D0);
> -
> - if (ret) {
> - dev_err(ipc_pcie->dev, "pci_set_power_state error=%d", ret);
> - return ret;
> - }
> -
> - pci_restore_state(ipc_pcie->pci);
> -
> /* The HAL shall inform the shared memory layer that the device is
> * active.
> */
> ipc_imem_pm_resume(ipc_pcie->imem);
>
> dev_dbg(ipc_pcie->dev, "RESUME done");
> - return ret;
> + return 0;
> }
>
> static int __maybe_unused ipc_pcie_suspend_cb(struct device *dev)
> --
> 2.33.1
>
next prev parent reply other threads:[~2021-12-29 20:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-24 8:19 [PATCH 1/2] net: wwan: iosm: Let PCI core handle PCI power transition Kai-Heng Feng
2021-12-24 8:19 ` [PATCH 2/2] net: wwan: iosm: Keep device at D0 for s2idle case Kai-Heng Feng
2021-12-29 20:18 ` Bjorn Helgaas
2021-12-30 1:00 ` Kai-Heng Feng
2022-01-03 15:28 ` Kumar, M Chetan
2022-01-03 17:21 ` Jakub Kicinski
2022-01-04 2:23 ` Kai-Heng Feng
2021-12-27 12:30 ` [PATCH 1/2] net: wwan: iosm: Let PCI core handle PCI power transition patchwork-bot+netdevbpf
2021-12-29 20:12 ` Bjorn Helgaas [this message]
2021-12-30 0:57 ` Kai-Heng Feng
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