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* [PATCH v2 0/5] Add quirks to proceed PME handshake in DWC PM
@ 2025-06-18  2:41 Richard Zhu
  2025-06-18  2:41 ` [PATCH v2 1/5] PCI: imx6: Don't poll LTSSM state of i.MX6QP PCIe in PM operations Richard Zhu
                   ` (4 more replies)
  0 siblings, 5 replies; 11+ messages in thread
From: Richard Zhu @ 2025-06-18  2:41 UTC (permalink / raw)
  To: frank.li, l.stach, lpieralisi, kwilczynski, mani, robh, bhelgaas,
	shawnguo, s.hauer, kernel, festevam
  Cc: linux-pci, linux-arm-kernel, imx, linux-kernel

Refer to PCIe r6.0, sec 5.2, fig 5-1 Link Power Management State Flow
Diagram. Both L0 and L2/L3 Ready can be transferred to LDn directly.

It's harmless to let dw_pcie_suspend_noirq() proceed suspend after the
PME_Turn_Off is sent out, whatever the LTSSM state is in L2 or L3 after
a recommended 10ms max wait refer to PCIe r6.0, sec 5.3.3.2.1 PME
Synchronization.

The LTSSM states of i.MX6QP PCIe is inaccessible after the PME_Turn_Off
is kicked off. To handle this case, don't poll L2 state and add one max
10ms delay if QUIRK_NOL2POLL_IN_PM flag is existing in suspend.

Main chenages in v2:
Add the following two patches.
- Skip PME_Turn_Off message if there is no endpoint connected.
- Don't return error when wait for link up.
v1:https://patchwork.kernel.org/project/linux-pci/cover/20250408065221.1941928-1-hongxing.zhu@nxp.com/

[PATCH v2 1/5] PCI: imx6: Don't poll LTSSM state of i.MX6QP PCIe in
[PATCH v2 2/5] PCI: imx6: Don't poll LTSSM state of i.MX7D PCIe in PM
[PATCH v2 3/5] PCI: dwc: Don't poll L2 if QUIRK_NOL2POLL_IN_PM is
[PATCH v2 4/5] PCI: dwc: Skip PME_Turn_Off message if there is no
[PATCH v2 5/5] PCI: dwc: Don't return error when wait for link up

drivers/pci/controller/dwc/pci-imx6.c             |  4 ++++
drivers/pci/controller/dwc/pcie-designware-host.c | 50 +++++++++++++++++++++++++++++++-------------------
drivers/pci/controller/dwc/pcie-designware.h      |  4 ++++
3 files changed, 39 insertions(+), 19 deletions(-)




^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2025-06-18 19:25 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-06-18  2:41 [PATCH v2 0/5] Add quirks to proceed PME handshake in DWC PM Richard Zhu
2025-06-18  2:41 ` [PATCH v2 1/5] PCI: imx6: Don't poll LTSSM state of i.MX6QP PCIe in PM operations Richard Zhu
2025-06-18 18:36   ` Frank Li
2025-06-18  2:41 ` [PATCH v2 2/5] PCI: imx6: Don't poll LTSSM state of i.MX7D " Richard Zhu
2025-06-18 18:34   ` Frank Li
2025-06-18  2:41 ` [PATCH v2 3/5] PCI: dwc: Don't poll L2 if QUIRK_NOL2POLL_IN_PM is existing in suspend Richard Zhu
2025-06-18 18:32   ` Frank Li
2025-06-18  2:41 ` [PATCH v2 4/5] PCI: dwc: Skip PME_Turn_Off message if there is no endpoint connected Richard Zhu
2025-06-18 18:19   ` Frank Li
2025-06-18  2:41 ` [PATCH v2 5/5] PCI: dwc: Don't return error when wait for link up Richard Zhu
2025-06-18 18:24   ` Frank Li

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