| From 0472bf06c6fd33c1a18aaead4c8f91e5a03d8d7b Mon Sep 17 00:00:00 2001 |
| From: Mathias Nyman <mathias.nyman@linux.intel.com> |
| Date: Wed, 5 Dec 2018 14:22:39 +0200 |
| Subject: xhci: Prevent U1/U2 link pm states if exit latency is too long |
| |
| From: Mathias Nyman <mathias.nyman@linux.intel.com> |
| |
| commit 0472bf06c6fd33c1a18aaead4c8f91e5a03d8d7b upstream. |
| |
| Don't allow USB3 U1 or U2 if the latency to wake up from the U-state |
| reaches the service interval for a periodic endpoint. |
| |
| This is according to xhci 1.1 specification section 4.23.5.2 extra note: |
| |
| "Software shall ensure that a device is prevented from entering a U-state |
| where its worst case exit latency approaches the ESIT." |
| |
| Allowing too long exit latencies for periodic endpoint confuses xHC |
| internal scheduling, and new devices may fail to enumerate with a |
| "Not enough bandwidth for new device state" error from the host. |
| |
| Cc: <stable@vger.kernel.org> |
| Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/usb/host/xhci.c | 16 ++++++++++++++++ |
| 1 file changed, 16 insertions(+) |
| |
| --- a/drivers/usb/host/xhci.c |
| +++ b/drivers/usb/host/xhci.c |
| @@ -4377,6 +4377,14 @@ static u16 xhci_calculate_u1_timeout(str |
| { |
| 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 |
| @@ -4433,6 +4441,14 @@ static u16 xhci_calculate_u2_timeout(str |
| { |
| 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 |
