>From: Alan Stern [mailto:stern@xxxxxxxxxxxxxxxxxxx] >On Fri, 21 Oct 2016, Sriram Dash wrote: > >> For the USB3.0 controller, USB 2.0 reset not driven while port is in >> Resume state. So, do not program the USB 2.0 reset >> (PORTSC[PR]=1) while in Resume state. >> >> Signed-off-by: Rajat Srivastava <rajat.srivastava@xxxxxxx> >> Signed-off-by: Sriram Dash <sriram.dash@xxxxxxx> >> Signed-off-by: Rajesh Bhagat <rajesh.bhagat@xxxxxxx> >> --- >> drivers/usb/host/xhci-hub.c | 28 +++++++++++++++++++++++++++- >> drivers/usb/host/xhci.h | 1 + >> 2 files changed, 28 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c >> index 730b9fd..3def0dd 100644 >> --- a/drivers/usb/host/xhci-hub.c >> +++ b/drivers/usb/host/xhci-hub.c >> @@ -878,7 +878,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, >u16 wValue, >> struct xhci_hcd *xhci = hcd_to_xhci(hcd); >> int max_ports; >> unsigned long flags; >> - u32 temp, status; >> + u32 temp, status, tmp_status = 0; >> int retval = 0; >> __le32 __iomem **port_array; >> int slot_id; >> @@ -1098,6 +1098,32 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 >typeReq, u16 wValue, >> spin_lock_irqsave(&xhci->lock, flags); >> break; >> case USB_PORT_FEAT_RESET: >> + /* >> + * Erratum : A010129 >> + * Synopsys STAR 9000962562. >> + * USB 2.0 Reset Not Driven While Port in Resume >> + * While in USB 2.0 resume state (the PORTSC.PLS >> + * register bit is set to 4'd15), if the xHCI driver >> + * programs the PORTSC.PR register bit to 1, the >> + * controller does not drive a USB 2.0 reset >> + * and it does not generate a PORTSC.PRC=1 interrupt. >> + * So, The xHCI driver should not program a USB >> + * 2.0 reset (PORTSC.PR=1) while in resume >> + * (PORTSC.PLS=4'd15). >> + */ >> + if (xhci->quirks & XHCI_PORT_RST_ON_RESUME) { > >It's always a bad idea to drive a reset signal while a port is resuming. We don't >need a quirk flag for this. Hi Alan, Ok. Then I will make it generic for xhci in the next version. >The HCD should never do it, and the USB core should >never tell the HCD to do it. > >Alan Stern -- 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
