Merge tag 'usb-4.20-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB fixes from Greg KH:
 "Here are some small USB fixes for 4.20-rc6

  The "largest" here are some xhci fixes for reported issues. Also here
  is a USB core fix, some quirk additions, and a usb-serial fix which
  required the export of one of the tty layer's functions to prevent
  code duplication. The tty maintainer agreed with this change.

  All of these have been in linux-next with no reported issues"

* tag 'usb-4.20-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  xhci: Prevent U1/U2 link pm states if exit latency is too long
  xhci: workaround CSS timeout on AMD SNPS 3.0 xHC
  USB: check usb_get_extra_descriptor for proper size
  USB: serial: console: fix reported terminal settings
  usb: quirk: add no-LPM quirk on SanDisk Ultra Flair device
  USB: Fix invalid-free bug in port_over_current_notify()
  usb: appledisplay: Add 27" Apple Cinema Display

1 files changed, 38 insertions, 4 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index c928dbbff881..dae3be1b9c8f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -968,6 +968,7 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup)
         unsigned int            delay = XHCI_MAX_HALT_USEC;
         struct usb_hcd          *hcd = xhci_to_hcd(xhci);
         u32                     command;
+        u32                     res;
 
         if (!hcd->state)
                 return 0;
@@ -1021,11 +1022,28 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup)
         command = readl(&xhci->op_regs->command);
         command |= CMD_CSS;
         writel(command, &xhci->op_regs->command);
+        xhci->broken_suspend = 0;
         if (xhci_handshake(&xhci->op_regs->status,
                                 STS_SAVE, 0, 10 * 1000)) {
-                xhci_warn(xhci, "WARN: xHC save state timeout\n");
-                spin_unlock_irq(&xhci->lock);
-                return -ETIMEDOUT;
+        /*
+         * AMD SNPS xHC 3.0 occasionally does not clear the
+         * SSS bit of USBSTS and when driver tries to poll
+         * to see if the xHC clears BIT(8) which never happens
+         * and driver assumes that controller is not responding
+         * and times out. To workaround this, its good to check
+         * if SRE and HCE bits are not set (as per xhci
+         * Section 5.4.2) and bypass the timeout.
+         */
+                res = readl(&xhci->op_regs->status);
+                if ((xhci->quirks & XHCI_SNPS_BROKEN_SUSPEND) &&
+                    (((res & STS_SRE) == 0) &&
+                                ((res & STS_HCE) == 0))) {
+                        xhci->broken_suspend = 1;
+                } else {
+                        xhci_warn(xhci, "WARN: xHC save state timeout\n");
+                        spin_unlock_irq(&xhci->lock);
+                        return -ETIMEDOUT;
+                }
         }
         spin_unlock_irq(&xhci->lock);
 
@@ -1078,7 +1096,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
         set_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags);
 
         spin_lock_irq(&xhci->lock);
-        if (xhci->quirks & XHCI_RESET_ON_RESUME)
+        if ((xhci->quirks & XHCI_RESET_ON_RESUME) || xhci->broken_suspend)
                 hibernated = true;
 
         if (!hibernated) {
@@ -4496,6 +4514,14 @@ static u16 xhci_calculate_u1_timeout(struct xhci_hcd *xhci,
 {
         unsigned long long timeout_ns;
 
+        /* Prevent U1 if service interval is shorter than U1 exit latency */
+        if (usb_endpoint_xfer_int(desc) || usb_endpoint_xfer_isoc(desc)) {
+                if (xhci_service_interval_to_ns(desc) <= udev->u1_params.mel) {
+                        dev_dbg(&udev->dev, "Disable U1, ESIT shorter than exit latency\n");
+                        return USB3_LPM_DISABLED;
+                }
+        }
+
         if (xhci->quirks & XHCI_INTEL_HOST)
                 timeout_ns = xhci_calculate_intel_u1_timeout(udev, desc);
         else
@@ -4552,6 +4578,14 @@ static u16 xhci_calculate_u2_timeout(struct xhci_hcd *xhci,
 {
         unsigned long long timeout_ns;
 
+        /* Prevent U2 if service interval is shorter than U2 exit latency */
+        if (usb_endpoint_xfer_int(desc) || usb_endpoint_xfer_isoc(desc)) {
+                if (xhci_service_interval_to_ns(desc) <= udev->u2_params.mel) {
+                        dev_dbg(&udev->dev, "Disable U2, ESIT shorter than exit latency\n");
+                        return USB3_LPM_DISABLED;
+                }
+        }
+
         if (xhci->quirks & XHCI_INTEL_HOST)
                 timeout_ns = xhci_calculate_intel_u2_timeout(udev, desc);
         else