`quirk_usb_handoff_ohci` takes over 73 ms (twice) on AMD system (was: `pci_apply_final_quirks()` taking half a second)

From: Paul Menzel
Date: Sun Jun 24 2018 - 12:50:14 EST

Dear Alan,


Sorry for the long delay.

Am 31.12.2017 um 22:16 schrieb Alan Stern:
On Sun, 31 Dec 2017, Paul Menzel wrote:

Am 29.12.2017 um 17:14 schrieb Alan Stern:
On Thu, 28 Dec 2017, Bjorn Helgaas wrote:

On Tue, Dec 26, 2017 at 04:55:20PM +0100, Paul Menzel wrote:

[â]

So itâs `pci fixup quirk_usb_early_handoff` taking around 85 ms, and
that twice.

Wow. That's pretty painful, but of course I don't know how to fix it.
From looking at quirk_usb_early_handoff(), it may depend on BIOS
details. Maybe the USB folks will have some ideas.

Can we see the output from lspci? It would help to know what the 12.0
and 13.0 devices are.

Sorry, that was trimmed from the original message. Here is the output
from the ASRock A780FullD.

```
$ more /proc/version
Linux version 4.9.0-0.bpo.2-amd64 (debian-kernel@xxxxxxxxxxxxxxxx)
(gcc version 4.9.2 (Debian 4.9.2-10) ) #1 SMP Debian 4.9.13-1~bpo8+1 (2017-02-27)
$ lspci -nn

00:12.0 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB OHCI0 Controller [1002:4397]
00:12.1 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0 USB OHCI1 Controller [1002:4398]
00:12.2 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB EHCI Controller [1002:4396]
00:13.0 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB OHCI0 Controller [1002:4397]
00:13.1 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0 USB OHCI1 Controller [1002:4398]
00:13.2 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB EHCI Controller [1002:4396]

So far, this can be reproduce on all AMD systems I have (ASRock
A780FullHD, ASRock E350M1, Asus F2A85-M Pro).

So they are OHCI controllers. You could add some debugging statements
to quirk_usb_handoff_ohci() to try and locate the part that's taking so
long.

737 static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
738 {
739 void __iomem *base;
740 u32 control;
741 u32 fminterval = 0;
742 bool no_fminterval = false;
743 int cnt;
744 745 if (!mmio_resource_enabled(pdev, 0))
746 return;
747 748 base = pci_ioremap_bar(pdev, 0);
749 if (base == NULL)
750 return;
751 752 /*
753 * ULi M5237 OHCI controller locks the whole system when accessing
754 * the OHCI_FMINTERVAL offset.
755 */
756 if (pdev->vendor == PCI_VENDOR_ID_AL && pdev->device == 0x5237)
757 no_fminterval = true;
758 759 control = readl(base + OHCI_CONTROL);
760 761 printk(KERN_INFO "1\n");
762 /* On PA-RISC, PDC can leave IR set incorrectly; ignore it there. */
763 #ifdef __hppa__
764 #define OHCI_CTRL_MASK (OHCI_CTRL_RWC | OHCI_CTRL_IR)
765 #else
766 #define OHCI_CTRL_MASK OHCI_CTRL_RWC
767 768 if (control & OHCI_CTRL_IR) {
769 int wait_time = 500; /* arbitrary; 5 seconds */
770 writel(OHCI_INTR_OC, base + OHCI_INTRENABLE);
771 writel(OHCI_OCR, base + OHCI_CMDSTATUS);
772 while (wait_time > 0 &&
773 readl(base + OHCI_CONTROL) & OHCI_CTRL_IR) {
774 wait_time -= 10;
775 msleep(10);
776 }
777 if (wait_time <= 0)
778 dev_warn(&pdev->dev,
779 "OHCI: BIOS handoff failed (BIOS bug?) %08x\n",
780 readl(base + OHCI_CONTROL));
781 }
782 #endif
783 784 printk(KERN_INFO "2\n");
785 /* disable interrupts */
786 writel((u32) ~0, base + OHCI_INTRDISABLE);
787 788 printk(KERN_INFO "3\n");
789 /* Reset the USB bus, if the controller isn't already in RESET */
790 if (control & OHCI_HCFS) {
791 /* Go into RESET, preserving RWC (and possibly IR) */
792 writel(control & OHCI_CTRL_MASK, base + OHCI_CONTROL);
793 readl(base + OHCI_CONTROL);
794 795 /* drive bus reset for at least 50 ms (7.1.7.5) */
796 msleep(50);
797 }
798 printk(KERN_INFO "4\n");
799 800 /* software reset of the controller, preserving HcFmInterval */
801 if (!no_fminterval)
802 fminterval = readl(base + OHCI_FMINTERVAL);
803 804 writel(OHCI_HCR, base + OHCI_CMDSTATUS);
805 printk(KERN_INFO "5\n");
806 807 /* reset requires max 10 us delay */
808 for (cnt = 30; cnt > 0; --cnt) { /* ... allow extra time */
809 printk(KERN_INFO "6 cnt = %d\n", cnt);
810 if ((readl(base + OHCI_CMDSTATUS) & OHCI_HCR) == 0)
811 break;
812 udelay(1);
813 }
814 815 printk(KERN_INFO "7\n");
816 if (!no_fminterval)
817 writel(fminterval, base + OHCI_FMINTERVAL);
818 819 /* Now the controller is safely in SUSPEND and nothing can wake it up */
820 iounmap(base);
821 }

Here is the result.

[ 0.062796] pci 0000:00:12.0: calling quirk_usb_early_handoff+0x0/0x700 @ 1
[ 0.062860] 1
[ 0.086662] 2

Around 24 ms are spent in the loop checking `readl(base + OHCI_CONTROL) & OHCI_CTRL_IR)` in line 772.

[ 0.086663] 3
[ 0.138645] 4

Thatâs the 50 ms from resetting the USB bus, if the controller isn't already in RESET in line 796.

[ 0.138647] 5
[ 0.138649] 6 cnt = 30
[ 0.138650] 7
[ 0.138771] pci 0000:00:12.0: quirk_usb_early_handoff+0x0/0x700 took 74188 usecs
[ 0.138778] pci 0000:00:12.2: calling quirk_usb_early_handoff+0x0/0x700 @ 1
[ 0.138917] pci 0000:00:12.2: quirk_usb_early_handoff+0x0/0x700 took 133 usecs
[ 0.138919] pci 0000:00:12.2: calling pci_fixup_amd_ehci_pme+0x0/0x30 @ 1
[ 0.138920] pci 0000:00:12.2: PME# does not work under D3, disabling it
[ 0.138922] pci 0000:00:12.2: pci_fixup_amd_ehci_pme+0x0/0x30 took 0 usecs
[ 0.138926] pci 0000:00:13.0: calling quirk_usb_early_handoff+0x0/0x700 @ 1
[ 0.138987] 1
[ 0.161639] 2
[ 0.161640] 3
[ 0.213622] 4
[ 0.213625] 5
[ 0.213626] 6 cnt = 30
[ 0.213627] 7
[ 0.213748] pci 0000:00:13.0: quirk_usb_early_handoff+0x0/0x700 took 73062 usecs

So, is there a way to not reset the controller? In my case the firmware and GRUB already used the controller and set it up.

Additionally, can this be done in parallel for both PCI devices?

Can you think of other ways to decrease the time?


Kind regards,

Paul