Re: [PATCH 2/2] net: wwan: iosm: Keep device at D0 for s2idle case
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2021-12-29 20:18:23
Also in:
linux-pci, linux-pm, lkml
[+cc Rafael, Vaibhav] On Fri, Dec 24, 2021 at 04:19:14PM +0800, Kai-Heng Feng wrote:
quoted hunk ↗ jump to hunk
We are seeing spurious wakeup caused by Intel 7560 WWAN on AMD laptops. This prevent those laptops to stay in s2idle state. From what I can understand, the intention of ipc_pcie_suspend() is to put the device to D3cold, and ipc_pcie_suspend_s2idle() is to keep the device at D0. However, the device can still be put to D3hot/D3cold by PCI core. So explicitly let PCI core know this device should stay at D0, to solve the spurious wakeup. Signed-off-by: Kai-Heng Feng <redacted> --- drivers/net/wwan/iosm/iosm_ipc_pcie.c | 3 +++ 1 file changed, 3 insertions(+)diff --git a/drivers/net/wwan/iosm/iosm_ipc_pcie.c b/drivers/net/wwan/iosm/iosm_ipc_pcie.c index d73894e2a84ed..af1d0e837fe99 100644 --- a/drivers/net/wwan/iosm/iosm_ipc_pcie.c +++ b/drivers/net/wwan/iosm/iosm_ipc_pcie.c@@ -340,6 +340,9 @@ static int __maybe_unused ipc_pcie_suspend_s2idle(struct iosm_pcie *ipc_pcie) ipc_imem_pm_s2idle_sleep(ipc_pcie->imem, true); + /* Let PCI core know this device should stay at D0 */ + pci_save_state(ipc_pcie->pci);
This is a weird and non-obvious way to say "this device should stay at D0". It's also fairly expensive since pci_save_state() does a lot of slow PCI config reads.
return 0; } -- 2.33.1