Re: Regression causes a hang on boot with a Comtrol PCI card

From: Mathias Nyman
Date: Tue Apr 02 2019 - 10:46:53 EST

On 2.4.2019 17.29, Alan Stern wrote:
On Mon, 1 Apr 2019, Bjorn Helgaas wrote:

[+cc Mathias, Greg, Alan, linux-usb]

Beginning of thread:

Synopsis: v5.0 hangs at boot unless the following commits are reverted:

1302fcf0d03e ("PCI: Configure *all* devices, not just hot-added ones")
1c3c5eab1715 ("sched/core: Enable might_sleep() and smp_processor_id() checks early")

The hang appears to be in quirk_usb_early_handoff(). With
"initcall_debug", we see the call but not the completion:

On Fri, Mar 22, 2019 at 03:02:11PM -0500, Jesse Hathaway wrote:
So apparently the hang happens while we're running the "final" PCI
fixups. This happens after all the rest of PCI is initialized.

Can you boot v5.0 vanilla with "initcall_debug"? Maybe we can narrow
it down to a specific quirk.

yup, added the "initcall_debug" output to the ticket:, here is the tail end

[ 14.896337] NET: Registered protocol family 1
[ 14.901314] initcall af_unix_init+0x0/0x4e returned 0 after 4866 usecs
[ 14.908694] calling ipv6_offload_init+0x0/0x7f @ 1
[ 14.914238] initcall ipv6_offload_init+0x0/0x7f returned 0 after 1 usecs
[ 14.921821] calling vlan_offload_init+0x0/0x20 @ 1
[ 14.927365] initcall vlan_offload_init+0x0/0x20 returned 0 after 0 usecs
[ 14.934948] calling pci_apply_final_quirks+0x0/0x126 @ 1
[ 14.941106] pci 0000:00:1a.0: calling quirk_usb_early_handoff+0x0/0x6a0 @ 1

thanks, Jesse Hathaway

Most likely the problem occurs somewhere inside
quirk_usb_handoff_xhci(). Can Jesse add debugging statements to that
routine in order to pin down exactly where the problem lies?

Alan Stern

lspci log from bugzilla shows 0000:00:1a.0 is a EHCI device,
so probably woth adding debugging to quirk_usb_disable_ehci() as well

00:1a.0 USB controller: Intel Corporation C610/X99 series chipset USB Enhanced Host Controller #2 (rev 05) (prog-if 20 [EHCI])