From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Mario Limonciello <mario.limonciello@dell.com>,
Anthony Wong <anthony.wong@canonical.com>,
Linux ACPI <linux-acpi@vger.kernel.org>,
Linux PCI <linux-pci@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Andreas Noever <andreas.noever@gmail.com>,
Michael Jamet <michael.jamet@intel.com>,
Yehezkel Bernat <YehezkelShB@gmail.com>
Subject: Re: [Regression] Commit "ACPI: PM: Allow transitions to D0 to occur in special cases"
Date: Thu, 01 Aug 2019 00:26:51 +0200 [thread overview]
Message-ID: <6494680.N7F1gMbocb@kreacher> (raw)
In-Reply-To: <20190731213001.GC151852@google.com>
On Wednesday, July 31, 2019 11:30:01 PM CEST Bjorn Helgaas wrote:
> [+cc Thunderbolt folks, see
> https://lore.kernel.org/r/578BD3F1-B185-471B-A3EB-FF71BA34B822@canonical.com
> for beginning of thread]
>
> On Thu, Aug 01, 2019 at 12:04:29AM +0800, Kai-Heng Feng wrote:
> > Hi,
> >
> > After commit "ACPI: PM: Allow transitions to D0 to occur in special cases”,
>
> This is f850a48a0799 ("ACPI: PM: Allow transitions to D0 to occur in
> special cases").
>
> > Thunderbolt on XPS 9380 spews the following when it runtime resumes:
> > [ 36.136554] pci_raw_set_power_state: 25 callbacks suppressed
> > [ 36.136558] pcieport 0000:03:00.0: Refused to change power state,
> > currently in D3
>
> We really should be smarter about what we print here, maybe something
> like the patch below?
>
> pci_raw_set_power_state() prints "Refused to change power state" if
> (in this case) the value of (PCI_PM_CTRL & PCI_PM_CTRL_STATE_MASK) is
> 0x3. Most likely we got 0xffff from PCI_PM_CTRL because the device is
> in D3cold. If the device is in D3cold, pci_raw_set_power_state() has
> no hope of doing anything because it only uses PCI PM config
> registers, and they're inaccessible in D3cold.
>
> Presumably there's some platform PM method that is supposed to take
> the device out of D3cold, and maybe we're missing that somehow?
Yes, there is.
> Based on an lspci I found at [1], I suspect 03:00.0 is a Thunderbolt
> switch leading to [bus 04-6d]. From your log, it looks like these
> devices don't work:
>
> 03:00.0 Thunderbolt Upstream Port
> 04:00.0 Thunderbolt Downstream Port
> 04:01.0 Thunderbolt Downstream Port (Slot 1)
> 04:02.0 Thunderbolt Downstream Port
> 04:04.0 Thunderbolt Downstream Port (Slot 4)
> 05:00.0 Thunderbolt NHI
> 39:00.0 XHCI USB
>
> If 03:00.0 is stuck in D3cold, that would explain why none of these
> things work.
>
> [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1826125
>
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 29ed5ec1ac27..63ca963ebff9 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -851,6 +852,11 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
> return -EIO;
>
> pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
> + if (pmcsr == (u16) ~0) {
Is the "device not accessible" the only case in which we can get all ones from this?
If so, the change will be fine by me.
> + pci_err(dev, "device not responding; can't change to power state D%d\n",
> + state);
But I wouldn't break this line.
> + return -EIO;
> + }
>
> /*
> * If we're (effectively) in D3, force entire word to 0.
>
Thanks!
next prev parent reply other threads:[~2019-07-31 22:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 16:04 [Regression] Commit "ACPI: PM: Allow transitions to D0 to occur in special cases" Kai-Heng Feng
2019-07-31 16:12 ` Mario.Limonciello
2019-07-31 21:30 ` Bjorn Helgaas
2019-07-31 22:26 ` Rafael J. Wysocki [this message]
2019-08-02 22:36 ` Bjorn Helgaas
2019-07-31 22:20 ` Rafael J. Wysocki
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