Re: [PATCH 1/2] net: wwan: iosm: Let PCI core handle PCI power transition
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2021-12-29 20:12:34
Also in:
linux-pci, lkml, netdev
[+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...
quoted hunk ↗ jump to hunk
Signed-off-by: Kai-Heng Feng <redacted> --- 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