2022-02-09 16:41:47

by Fabrice Gasnier

Subject: [PATCH] usb: dwc2: drd: fix soft connect when gadget is unconfigured

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 <[email protected]>
---
drivers/usb/dwc2/drd.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
index 1b39c47..9b6d44d 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 (hsotg->enabled) {
+ /* 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

2022-02-10 17:46:37

by Amelie Delaunay

Subject: Re: [PATCH] usb: dwc2: drd: fix soft connect when gadget is unconfigured

On 2/9/22 17:15, Fabrice Gasnier wrote:
> 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 <[email protected]>

Thanks for your patch,

Reviewed-by: Amelie Delaunay <[email protected]>

Regards,
Amelie

> ---
> drivers/usb/dwc2/drd.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
> index 1b39c47..9b6d44d 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 (hsotg->enabled) {
> + /* This clear DCTL.SFTDISCON bit */
> + dwc2_hsotg_core_connect(hsotg);
> + }
> } else {
> if (dwc2_is_device_mode(hsotg)) {
> if (!dwc2_ovr_bvalid(hsotg, false))

2022-02-11 18:02:19

by Minas Harutyunyan

Subject: Re: [PATCH] usb: dwc2: drd: fix soft connect when gadget is unconfigured

On 2/9/2022 8:15 PM, Fabrice Gasnier wrote:
> 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 <[email protected]>

Acked-by: Minas Harutyunyan <[email protected]>

> ---
> drivers/usb/dwc2/drd.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
> index 1b39c47..9b6d44d 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 (hsotg->enabled) {
> + /* This clear DCTL.SFTDISCON bit */
> + dwc2_hsotg_core_connect(hsotg);
> + }
> } else {
> if (dwc2_is_device_mode(hsotg)) {
> if (!dwc2_ovr_bvalid(hsotg, false))