In DWC3 versions < 2.50a configured without Hibernation mode enabled, there will be an extra link status change interrupt if device detects host-initiated U3 exit.
In that case, core will generate an unnecessary U3 -> RESUME transition which should be ignored by the driver. Signed-off-by: Felipe Balbi <[email protected]> --- drivers/usb/dwc3/gadget.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index a04342f..39d8e5a 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2280,6 +2280,34 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc, unsigned int evtinfo) { enum dwc3_link_state next = evtinfo & DWC3_LINK_STATE_MASK; + unsigned int pwropt; + + /* + * WORKAROUND: DWC3 < 2.50a have an issue when configured without + * Hibernation mode enabled which would show up when device detects + * host-initiated U3 exit. + * + * In that case, device will generate a Link State Change Interrupt + * from U3 to RESUME which is only necessary if Hibernation is + * configured in. + * + * There are no functional changes due to such spurious event and we + * just need to ignore it. + * + * Refers to: + * + * STAR#9000570034 RTL: SS Resume event generated in non-Hibernation + * operational mode + */ + pwropt = DWC3_GHWPARAMS1_EN_PWROPT(dwc->hwparams.hwparams1); + if ((dwc->revision < DWC3_REVISION_250A) && + (pwropt != DWC3_GHWPARAMS1_EN_PWROPT_HIB)) { + if ((dwc->link_state == DWC3_LINK_STATE_U3) && + (next == DWC3_LINK_STATE_RESUME)) { + dev_vdbg(dwc->dev, "ignoring transition U3 -> Resume\n"); + return; + } + } /* * WORKAROUND: DWC3 Revisions <1.83a have an issue which, depending -- 1.8.1.rc1.5.g7e0651a -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
