John, On Fri, Oct 30, 2015 at 1:38 PM, John Youn <John.Youn@xxxxxxxxxxxx> wrote: > On 10/16/2015 3:10 PM, Douglas Anderson wrote: >> If you've got your interrupt signals bouncing a bit as you insert your >> USB device, you might end up in a state when the device is connected but >> the driver doesn't know it. >> >> Specifically, the observed order is: >> 1. hardware sees connect >> 2. hardware sees disconnect >> 3. hardware sees connect >> 4. dwc2_port_intr() - clears connect interrupt >> 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() >> >> Now you'll be stuck with the cable plugged in and no further interrupts >> coming in but the driver will think we're disconnected. >> >> We'll fix this by checking for the missing connect interrupt and >> re-connecting after the disconnect is posted. We don't skip the >> disconnect because if there is a transitory disconnect we really want to >> de-enumerate and re-enumerate. >> >> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> >> --- >> drivers/usb/dwc2/core.h | 2 ++ >> drivers/usb/dwc2/hcd.c | 33 +++++++++++++++++++++++++++++++++ >> drivers/usb/dwc2/hcd_intr.c | 6 +----- >> 3 files changed, 36 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h >> index ebf2504..30748be 100644 >> --- a/drivers/usb/dwc2/core.h >> +++ b/drivers/usb/dwc2/core.h >> @@ -1151,11 +1151,13 @@ static inline int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, >> >> #if IS_ENABLED(CONFIG_USB_DWC2_HOST) || IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE) >> extern int dwc2_hcd_get_frame_number(struct dwc2_hsotg *hsotg); >> +extern void dwc2_hcd_connect(struct dwc2_hsotg *hsotg); >> extern void dwc2_hcd_disconnect(struct dwc2_hsotg *hsotg); >> extern void dwc2_hcd_start(struct dwc2_hsotg *hsotg); >> #else >> static inline int dwc2_hcd_get_frame_number(struct dwc2_hsotg *hsotg) >> { return 0; } >> +static inline void dwc2_hcd_connect(struct dwc2_hsotg *hsotg) {} >> static inline void dwc2_hcd_disconnect(struct dwc2_hsotg *hsotg) {} >> static inline void dwc2_hcd_start(struct dwc2_hsotg *hsotg) {} >> static inline void dwc2_hcd_remove(struct dwc2_hsotg *hsotg) {} >> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c >> index af4e4a2..4d2bc50 100644 >> --- a/drivers/usb/dwc2/hcd.c >> +++ b/drivers/usb/dwc2/hcd.c >> @@ -268,6 +268,22 @@ static void dwc2_hcd_cleanup_channels(struct dwc2_hsotg *hsotg) >> } >> >> /** >> + * dwc2_hcd_connect() - Handles connect of the HCD >> + * >> + * @hsotg: Pointer to struct dwc2_hsotg >> + * >> + * Must be called with interrupt disabled and spinlock held >> + */ >> +void dwc2_hcd_connect(struct dwc2_hsotg *hsotg) >> +{ >> + if (hsotg->lx_state != DWC2_L0) >> + usb_hcd_resume_root_hub(hsotg->priv); >> + >> + hsotg->flags.b.port_connect_status_change = 1; >> + hsotg->flags.b.port_connect_status = 1; >> +} >> + >> +/** >> * dwc2_hcd_disconnect() - Handles disconnect of the HCD >> * >> * @hsotg: Pointer to struct dwc2_hsotg >> @@ -277,6 +293,7 @@ static void dwc2_hcd_cleanup_channels(struct dwc2_hsotg *hsotg) >> void dwc2_hcd_disconnect(struct dwc2_hsotg *hsotg) >> { >> u32 intr; >> + u32 hprt0; >> >> /* Set status flags for the hub driver */ >> hsotg->flags.b.port_connect_status_change = 1; >> @@ -315,6 +332,22 @@ void dwc2_hcd_disconnect(struct dwc2_hsotg *hsotg) >> dwc2_hcd_cleanup_channels(hsotg); >> >> dwc2_host_disconnect(hsotg); >> + >> + /* >> + * Add an extra check here to see if we're actually connected but >> + * we don't have a detection interrupt pending. This can happen if: >> + * 1. hardware sees connect >> + * 2. hardware sees disconnect >> + * 3. hardware sees connect >> + * 4. dwc2_port_intr() - clears connect interrupt >> + * 5. dwc2_handle_common_intr() - calls here >> + * >> + * Without the extra check here we will end calling disconnect >> + * and won't get any future interrupts to handle the connect. >> + */ >> + hprt0 = dwc2_readl(hsotg->regs + HPRT0); >> + if (!(hprt0 & HPRT0_CONNDET) && (hprt0 & HPRT0_CONNSTS)) >> + dwc2_hcd_connect(hsotg); > > I'm a little bit wary of this as it will also run when you unload > the module with a device connected. However I can't produce any > negative results from that. Will it work if you handle it just > for the disconnect interrupt? Good call. I think it might actually be cleaner to just add a "force" parameter to dwc2_hcd_disconnect(). That way the 3 callers other than _dwc2_hcd_stop() all get the behavior to check for reconnect. I hope that's OK. New patch forthcoming. -Doug -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html