Re: [REGRESSION] usb controller fails to initialize on intel s1200btl

"Rafael J. Wysocki (Intel)" <[email protected]> Thu, 30 Jul 2026 18:16:27 +0200
Newsgroups gmane.linux.usb.general,gmane.linux.acpi.devel
Message-ID <CAJZ5v0jByxtQ2tmNm_ZyyBnDMBNjuqQwD_367NRyGNzF7wQtRw@mail.gmail.com>
On Thu, Jul 30, 2026 at 5:32 PM Julian Silver <[email protected]> wrote:
>
> On 2026-07-30 21:55:14, Rafael J. Wysocki (Intel) wrote:
> > Does adding "intel_idle.max_cstate=1" to the kernel command line also
> > help, by any chance?
>
> Yes. "intel_idle.max_cstate=1" also helps (on kernel 7.1.5).

Thanks for checking.

Can you please check if the attached patch (on top of the current
mainline) helps?
usb-ehci-pm-qos.patch (text/x-patch, 669 B)
---
 drivers/usb/host/ehci-pci.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -380,9 +380,17 @@ static const struct ehci_driver_override
 
 static int ehci_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
+	struct pm_qos_request req;
+	int ret;
+
 	if (is_bypassed_id(pdev))
 		return -ENODEV;
-	return usb_hcd_pci_probe(pdev, &ehci_pci_hc_driver);
+
+	cpu_latency_qos_add_request(&req, 10);
+	ret = usb_hcd_pci_probe(pdev, &ehci_pci_hc_driver);
+	cpu_latency_qos_remove_request(&req);
+
+	return ret;
 }
 
 static void ehci_pci_remove(struct pci_dev *pdev)