This is a note to let you know that I've just added the patch titled Revert "USB: xhci: fix U1/U2 handling for hardware with XHCI_INTEL_HOST quirk set" to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: revert-usb-xhci-fix-u1-u2-handling-for-hardware-with.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b6593a4d489a3e37ba70007d5cd067ba9bc9432d Author: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Date: Fri Aug 20 15:35:01 2021 +0300 Revert "USB: xhci: fix U1/U2 handling for hardware with XHCI_INTEL_HOST quirk set" [ Upstream commit 2847c46c61486fd8bca9136a6e27177212e78c69 ] This reverts commit 5d5323a6f3625f101dbfa94ba3ef7706cce38760. That commit effectively disabled Intel host initiated U1/U2 lpm for devices with periodic endpoints. Before that commit we disabled host initiated U1/U2 lpm if the exit latency was larger than any periodic endpoint service interval, this is according to xhci spec xhci 1.1 specification section 4.23.5.2 After that commit we incorrectly checked that service interval was smaller than U1/U2 inactivity timeout. This is not relevant, and can't happen for Intel hosts as previously set U1/U2 timeout = 105% * service interval. Patch claimed it solved cases where devices can't be enumerated because of bandwidth issues. This might be true but it's a side effect of accidentally turning off lpm. exit latency calculations have been revised since then Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210820123503.2605901-5-mathias.nyman@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index c4e3760abd5b..bebab0ec2978 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -4580,19 +4580,19 @@ static u16 xhci_calculate_u1_timeout(struct xhci_hcd *xhci, { unsigned long long timeout_ns; - if (xhci->quirks & XHCI_INTEL_HOST) - timeout_ns = xhci_calculate_intel_u1_timeout(udev, desc); - else - timeout_ns = udev->u1_params.sel; - /* 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) <= timeout_ns) { + 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 + timeout_ns = udev->u1_params.sel; + /* The U1 timeout is encoded in 1us intervals. * Don't return a timeout of zero, because that's USB3_LPM_DISABLED. */ @@ -4644,19 +4644,19 @@ static u16 xhci_calculate_u2_timeout(struct xhci_hcd *xhci, { unsigned long long timeout_ns; - if (xhci->quirks & XHCI_INTEL_HOST) - timeout_ns = xhci_calculate_intel_u2_timeout(udev, desc); - else - timeout_ns = udev->u2_params.sel; - /* 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) <= timeout_ns) { + 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 + timeout_ns = udev->u2_params.sel; + /* The U2 timeout is encoded in 256us intervals */ timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 256 * 1000); /* If the necessary timeout value is bigger than what we can set in the