From 96562a23cfaf909bfa28d878fb70ce18a25201b1 Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Mon, 16 Jan 2023 16:22:16 +0200 Subject: [PATCH] xhci: Detect lpm incapable xHC USB3 roothub ports from ACPI tables commit 74622f0a81d0c2bcfc39f9192b788124e8c7f0af upstream. USB3 ports on xHC hosts may have retimers that cause too long exit latency to work with native USB3 U1/U2 link power management states. For now only use usb_acpi_port_lpm_incapable() to evaluate if port lpm should be disabled while setting up the USB3 roothub. Other ways to identify lpm incapable ports can be added here later if ACPI _DSM does not exist. Limit this to Intel hosts for now, this is to my knowledge only an Intel issue. Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20230116142216.1141605-8-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-pci.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c index 90c71979ba5e..aff65cefead2 100644 --- a/drivers/usb/host/xhci-pci.c +++ b/drivers/usb/host/xhci-pci.c @@ -351,8 +351,38 @@ static void xhci_pme_acpi_rtd3_enable(struct pci_dev *dev) NULL); ACPI_FREE(obj); } + +static void xhci_find_lpm_incapable_ports(struct usb_hcd *hcd, struct usb_device *hdev) +{ + struct xhci_hcd *xhci = hcd_to_xhci(hcd); + struct xhci_hub *rhub = &xhci->usb3_rhub; + int ret; + int i; + + /* This is not the usb3 roothub we are looking for */ + if (hcd != rhub->hcd) + return; + + if (hdev->maxchild > rhub->num_ports) { + dev_err(&hdev->dev, "USB3 roothub port number mismatch\n"); + return; + } + + for (i = 0; i < hdev->maxchild; i++) { + ret = usb_acpi_port_lpm_incapable(hdev, i); + + dev_dbg(&hdev->dev, "port-%d disable U1/U2 _DSM: %d\n", i + 1, ret); + + if (ret >= 0) { + rhub->ports[i]->lpm_incapable = ret; + continue; + } + } +} + #else static void xhci_pme_acpi_rtd3_enable(struct pci_dev *dev) { } +static void xhci_find_lpm_incapable_ports(struct usb_hcd *hcd, struct usb_device *hdev) { } #endif /* CONFIG_ACPI */ /* called during probe() after chip reset completes */ @@ -388,6 +418,10 @@ static int xhci_pci_setup(struct usb_hcd *hcd) static int xhci_pci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev, struct usb_tt *tt, gfp_t mem_flags) { + /* Check if acpi claims some USB3 roothub ports are lpm incapable */ + if (!hdev->parent) + xhci_find_lpm_incapable_ports(hcd, hdev); + return xhci_update_hub_device(hcd, hdev, tt, mem_flags); }