Re: [PATCH 3/3] clk: qcom: gcc-sc7280: Update the .pwrsts for usb gdsc
From: Krishna Kurapati PSSNV
Date: Wed Sep 14 2022 - 04:42:29 EST
On 9/14/2022 12:39 PM, Johan Hovold wrote:
On Thu, Sep 01, 2022 at 03:47:56PM +0530, Rajendra Nayak wrote:
USB on sc7280 cannot support wakeups from low power states
if the GDSC is turned OFF. Update the .pwrsts for usb GDSC so it
only transitions to RET in low power.
It seems this isn't just needed for wakeup to work. On both sc7280 and
sc8280xp the controller doesn't resume properly if the domain has been
powered off (i.e. regardless of whether wakeup is enabled or not).
Hi Johan,
I believe you are referring to the reinit that happens in xhci resume
path after wakeup happens:
[ 48.675839] xhci-hcd xhci-hcd.14.auto: xHC error in resume, USBSTS
0x411, Reinit
I see that when USB GDSC is not in retention, we don't retain controller
state and go for reinit and re-enum of connected devices. We are seeing
an additional delay of around ~0.7 sec (in chromebooks running on
SC7280) in the wakeup path for re-enumeration of connected USB devices.
To avoid this, we wanted to put GDSC in retention during PM suspend.
Are you sure there's no state that needs to be retained regardless of
the wakeup setting?
Signed-off-by: Rajendra Nayak <quic_rjendra@xxxxxxxxxxx>
---
drivers/clk/qcom/gcc-sc7280.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/qcom/gcc-sc7280.c b/drivers/clk/qcom/gcc-sc7280.c
index 7ff64d4d5920..de29a034e725 100644
--- a/drivers/clk/qcom/gcc-sc7280.c
+++ b/drivers/clk/qcom/gcc-sc7280.c
@@ -3126,7 +3126,7 @@ static struct gdsc gcc_usb30_prim_gdsc = {
.pd = {
.name = "gcc_usb30_prim_gdsc",
},
- .pwrsts = PWRSTS_OFF_ON,
+ .pwrsts = PWRSTS_RET_ON,
.flags = VOTABLE,
};
And what about gcc_usb30_sec_gdsc?
Currently wakeup is not enabled on secondary controller as its not
required for end product platform (herobrine variant). So leaving the
usb30_sec_gdsc as it is for now.
Regards,
Krishna,