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xhci: Detect lpm incapable xHC USB3 roothub ports from ACPI tables

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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 <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20230116142216.1141605-8-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathias Nyman 2023-01-16 16:22:16 +02:00 committed by Greg Kroah-Hartman
parent 84e2e57769
commit afcb4e0ab8
1 changed files with 34 additions and 0 deletions

34
drivers/usb/host/xhci-pci.c

@ -339,8 +339,38 @@ 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 */
@ -376,6 +406,10 @@ 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);
}