When the gadget driver hasn't been (yet) configured, and the cable is
connected to a HOST, the SFTDISCON gets cleared unconditionally, so the
HOST tries to enumerate it.
At the host side, this can result in a stuck USB port or worse. When
getting lucky, some dmesg can be observed at the host side:
new high-speed USB device number ...
device descriptor read/64, error -110
Fix it in drd, by checking the enabled flag before calling
dwc2_hsotg_core_connect(). It will be called later, once configured,
by the normal flow:
- udc_bind_to_driver
- usb_gadget_connect
- dwc2_hsotg_pullup
- dwc2_hsotg_core_connect
Fixes: 17f934024e84 ("usb: dwc2: override PHY input signals with usb role switch support")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
---
Changes in v2:
- Fix build error: 'struct dwc2_hsotg' has no member named 'enabled';
as reported by the kernel test robot.
https://lore.kernel.org/all/202202112236.AwoOTtHO-lkp@xxxxxxxxx/
Add dwc2_is_device_enabled() macro to handle this.
---
drivers/usb/dwc2/core.h | 2 ++
drivers/usb/dwc2/drd.c | 6 ++++--
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 8a63da3..8a7751b 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -1418,6 +1418,7 @@ void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
#define dwc2_is_device_connected(hsotg) (hsotg->connected)
+#define dwc2_is_device_enabled(hsotg) ((hsotg)->enabled)
int dwc2_backup_device_registers(struct dwc2_hsotg *hsotg);
int dwc2_restore_device_registers(struct dwc2_hsotg *hsotg, int remote_wakeup);
int dwc2_gadget_enter_hibernation(struct dwc2_hsotg *hsotg);
@@ -1454,6 +1455,7 @@ static inline int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg,
int testmode)
{ return 0; }
#define dwc2_is_device_connected(hsotg) (0)
+#define dwc2_is_device_enabled(hsotg) (0)
static inline int dwc2_backup_device_registers(struct dwc2_hsotg *hsotg)
{ return 0; }
static inline int dwc2_restore_device_registers(struct dwc2_hsotg *hsotg,
diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
index 1b39c47..d8d6493 100644
--- a/drivers/usb/dwc2/drd.c
+++ b/drivers/usb/dwc2/drd.c
@@ -130,8 +130,10 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
already = dwc2_ovr_avalid(hsotg, true);
} else if (role == USB_ROLE_DEVICE) {
already = dwc2_ovr_bvalid(hsotg, true);
- /* This clear DCTL.SFTDISCON bit */
- dwc2_hsotg_core_connect(hsotg);
+ if (dwc2_is_device_enabled(hsotg)) {
+ /* This clear DCTL.SFTDISCON bit */
+ dwc2_hsotg_core_connect(hsotg);
+ }
} else {
if (dwc2_is_device_mode(hsotg)) {
if (!dwc2_ovr_bvalid(hsotg, false))
--
2.7.4
