During an xhci host controller reset (via `USBCMD.HCRST`), reading DWC3 registers can return zero instead of their actual values. This applies not only to registers within the xhci memory space but also those in the broader DWC3 IP block.
By default, the xhci driver doesn't wait for the reset handshake to complete during teardown. This can cause problems when the DWC3 controller is operating as a dual role device and is switching from host to device mode, the invalid register read caused by ongoing HCRST could lead to gadget mode startup failures and unintended register overwrites.
To mitigate this, enable xhci-full-reset-on-remove-quirk to ensure that xhci_reset() completes its full reset handshake during xhci removal.
Cc: stable@vger.kernel.org Fixes: 6ccb83d6c497 ("usb: xhci: Implement xhci_handshake_check_state() helper") Signed-off-by: Roy Luo royluo@google.com --- drivers/usb/dwc3/host.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c index b48e108fc8fe..ea865898308f 100644 --- a/drivers/usb/dwc3/host.c +++ b/drivers/usb/dwc3/host.c @@ -126,7 +126,7 @@ static int dwc3_host_get_irq(struct dwc3 *dwc)
int dwc3_host_init(struct dwc3 *dwc) { - struct property_entry props[6]; + struct property_entry props[7]; struct platform_device *xhci; int ret, irq; int prop_idx = 0; @@ -182,6 +182,9 @@ int dwc3_host_init(struct dwc3 *dwc) if (DWC3_VER_IS_WITHIN(DWC3, ANY, 300A)) props[prop_idx++] = PROPERTY_ENTRY_BOOL("quirk-broken-port-ped");
+ if (dwc->dr_mode == USB_DR_MODE_OTG) + props[prop_idx++] = PROPERTY_ENTRY_BOOL("xhci-full-reset-on-remove-quirk"); + if (prop_idx) { ret = device_create_managed_software_node(&xhci->dev, props, NULL); if (ret) {