diff options
| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2018-12-05 14:22:39 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-13 09:21:36 +0100 |
| commit | 7e5408959018c71e60273abd1561d434d398310a (patch) | |
| tree | 7ffe17649cec6e71e0aea399d549f0c30b3c3881 | |
| parent | 5f3c652e0f8c943c93f130cdcf05032b4d92ac37 (diff) | |
xhci: Prevent U1/U2 link pm states if exit latency is too long
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>
| -rw-r--r-- | drivers/usb/host/xhci.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 9dbf1583bd7a..e3fdc799ad6e 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -4417,6 +4417,14 @@ 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 @@ -4473,6 +4481,14 @@ 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 |