diff options
| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2018-12-05 15:22:39 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-06 15:00:10 +0300 |
| commit | 0472bf06c6fd33c1a18aaead4c8f91e5a03d8d7b (patch) | |
| tree | 429aa5236402a508f3144670dda76beec5dd189a /drivers/usb/host | |
| parent | a7d57abcc8a5bdeb53bbf8e87558e8e0a2c2a29d (diff) | |
| download | linux-0472bf06c6fd33c1a18aaead4c8f91e5a03d8d7b.tar.xz | |
xhci: Prevent U1/U2 link pm states if exit latency is too long
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>
Diffstat (limited to 'drivers/usb/host')
| -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 c20b85e28d81..dae3be1b9c8f 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -4514,6 +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 @@ -4570,6 +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 |