* Re: Fwd: [Bug 99751] New: Enormous resume delay, unless pcie_ports=compat
2015-06-12 18:01 ` Fwd: [Bug 99751] New: Enormous resume delay, unless pcie_ports=compat Bjorn Helgaas
@ 2015-06-13 1:26 ` Rafael J. Wysocki
0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2015-06-13 1:26 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: linux-pci, Rajat Jain, Yinghai Lu, alex.williamson,
Rafael Wysocki, Myron Stowe, Brown, Len
On Friday, June 12, 2015 01:01:27 PM Bjorn Helgaas wrote:
> FYI. There's more information and analysis, but no resolution yet, in
> the bugzilla.
pciehp_resume() seems to be problematic (and "pcie_ports=compat" probably
simply disables PCIe hotplug on that system).
> ---------- Forwarded message ----------
> From: <bugzilla-daemon@bugzilla.kernel.org>
> Date: Wed, Jun 10, 2015 at 11:25 AM
> Subject: [Bug 99751] New: Enormous resume delay, unless pcie_ports=compat
> To: bhelgaas@google.com
>
>
> https://bugzilla.kernel.org/show_bug.cgi?id=99751
>
> Bug ID: 99751
> Summary: Enormous resume delay, unless pcie_ports=compat
> Product: Drivers
> Version: 2.5
> Kernel Version: 3.15 through 4.1rc5
> Hardware: All
> OS: Linux
> Tree: Mainline
> Status: NEW
> Severity: normal
> Priority: P1
> Component: PCI
> Assignee: drivers_pci@kernel-bugs.osdl.org
> Reporter: lenb@kernel.org
> Regression: No
>
> Created attachment 179451
> --> https://bugzilla.kernel.org/attachment.cgi?id=179451&action=edit
> lspci -vvv output
>
> On a Dell XPS11 laptop, pcieport 0000:00:1c.0 takes
> several seconds to resume from suspend.
>
> Booting with "pcie_ports=compat", or
> building with CONFIG_HOTPLUG_PCI_PCIE=n
> makes this delay go away.
>
> I've tested Linux-3.14.44 and do not see this delay.
> I've tested Linux-3.15.0 and others up through 4.1-rc5
> and I do see this delay. So I'll mark this as a regression.
>
> while I use analyze_suspend.py to trace resume,
> initcall_debug is sufficient to show this delay in dmesg,
> and I notice some additional PCI warnings there:
>
> [ 55.897986] pciehp 0000:00:1c.0:pcie04: Link Training Error occurs
> [ 55.897988] pciehp 0000:00:1c.0:pcie04: Failed to check link status
> [ 55.897992] call 0000:00:1c.0+ returned 0 after 2197660 usecs
>
> (yes, that is 2.19 SECONDS -- where anything> 50ms for resume is considered
> slow)
>
> Unclear (to me) what pcie04 is...
>
> $ lspci
> 00:00.0 Host bridge: Intel Corporation Haswell-ULT DRAM Controller (rev 0b)
> 00:02.0 VGA compatible controller: Intel Corporation Device 0a1e (rev 0b)
> 00:03.0 Audio device: Intel Corporation Haswell-ULT HD Audio Controller (rev
> 0b)
> 00:04.0 Signal processing controller: Intel Corporation Device 0a03 (rev 0b)
> 00:14.0 USB controller: Intel Corporation 8 Series USB xHCI HC (rev 04)
> 00:16.0 Communication controller: Intel Corporation 8 Series HECI #0 (rev 04)
> 00:1b.0 Audio device: Intel Corporation 8 Series HD Audio Controller (rev 04)
> 00:1c.0 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 1 (rev e4)
> 00:1c.1 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 2 (rev e4)
> 00:1c.3 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 4 (rev e4)
> 00:1d.0 USB controller: Intel Corporation 8 Series USB EHCI #1 (rev 04)
> 00:1f.0 ISA bridge: Intel Corporation 8 Series LPC Controller (rev 04)
> 00:1f.2 SATA controller: Intel Corporation 8 Series SATA Controller 1 [AHCI
> mode] (rev 04)
> 00:1f.3 SMBus: Intel Corporation 8 Series SMBus Controller (rev 04)
> 00:1f.6 Signal processing controller: Intel Corporation 8 Series Thermal (rev
> 04)
> 05:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5249 PCI
> Express Card Reader (rev 01)
> 07:00.0 Network controller: Intel Corporation Wireless 7260 (rev 6b)
>
> This 04 item appears under 1c.0 when I ask lspci about topology:
> $ lspci -tv
> -[0000:00]-+-00.0 Intel Corporation Haswell-ULT DRAM Controller
> +-02.0 Intel Corporation Device 0a1e
> +-03.0 Intel Corporation Haswell-ULT HD Audio Controller
> +-04.0 Intel Corporation Device 0a03
> +-14.0 Intel Corporation 8 Series USB xHCI HC
> +-16.0 Intel Corporation 8 Series HECI #0
> +-1b.0 Intel Corporation 8 Series HD Audio Controller
> +-1c.0-[04]--
> +-1c.1-[05]----00.0 Realtek Semiconductor Co., Ltd. RTS5249 PCI
> Express Card Reader
> +-1c.3-[07]----00.0 Intel Corporation Wireless 7260
> +-1d.0 Intel Corporation 8 Series USB EHCI #1
> +-1f.0 Intel Corporation 8 Series LPC Controller
> +-1f.2 Intel Corporation 8 Series SATA Controller 1 [AHCI mode]
> +-1f.3 Intel Corporation 8 Series SMBus Controller
> \-1f.6 Intel Corporation 8 Series Thermal
>
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--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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