Re: [PATCH v6 0/5] PCI: qcom: Add system suspend & resume support

Manivannan Sadhasivam
2022-09-12T17:37:52Z

On Fri, Sep 09, 2022 at 02:14:39PM +0530, Krishna chaitanya chundru wrote:
> Add suspend and resume syscore ops.
>
> When system suspends, and if the link is in L1ss, disable the clocks
> and power down the phy so that system enters into low power state by
> parking link in L1ss to save the maximum power. And when the system
> resumes, enable the clocks back and power on phy if they are disabled
> in the suspend path.
>

You need to mention that you are only turning off the PCIe controller
clocks and PHY is still powered by a separate domain (MX) so the link
statys intact.

> we are doing this only when link is in l1ss but not in L2/L3 as
> nowhere we are forcing link to L2/L3 by sending PME turn off.
>
> is_suspended flag indicates if the clocks are disabled in the suspend
> path or not.
>
> There is access to Ep PCIe space to mask MSI/MSIX after pm suspend ops
> (getting hit by affinity changes while making CPUs offline during suspend,
> this will happen after devices are suspended (all phases of suspend ops)).
> When registered with pm ops there is a crash due to un-clocked access,
> as in the pm suspend op clocks are disabled. So, registering with syscore
> ops which will called after making CPUs offline.
>
> Make GDSC always on to ensure controller and its dependent clocks
> won't go down during system suspend.
>

Where is the changelog? You seem to have added PHY and CLK patches to
this series. You need to comment on that.

Thanks,
Mani

> Krishna chaitanya chundru (5):
> PCI: qcom: Add system suspend and resume support
> PCI: qcom: Add retry logic for link to be stable in L1ss
> phy: core: Add support for phy power down & power up
> phy: qcom: Add power down/up callbacks to pcie phy
> clk: qcom: Alwaya on pcie gdsc
>
> drivers/clk/qcom/gcc-sc7280.c | 2 +-
> drivers/pci/controller/dwc/pcie-qcom.c | 156 ++++++++++++++++++++++++++++++-
> drivers/phy/phy-core.c | 30 ++++++
> drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 50 ++++++++++
> include/linux/phy/phy.h | 20 ++++
> 5 files changed, 256 insertions(+), 2 deletions(-)
>
> --
> 2.7.4
>