linux-kernel - Re: Linux 4.15-rc2: Regression in resume from ACPI S3

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Date:   Thu, 14 Dec 2017 16:54:09 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Bjorn Helgaas <helgaas@...nel.org>,
        Maarten Lankhorst <dev@...ankhorst.nl>,
        Michal Hocko <mhocko@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        the arch/x86 maintainers <x86@...nel.org>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-pci@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: Linux 4.15-rc2: Regression in resume from ACPI S3

On Thursday, December 14, 2017 4:52:22 PM CET Thomas Gleixner wrote:
> On Thu, 14 Dec 2017, Rafael J. Wysocki wrote:
> > The problem here is that pci_pm_thaw_noirq() calls pci_restore_state() which
> > in fact requires the device to be in D0, so the caller should put it into
> > D0 instead of trying to "update" its power state.
> > 
> > [Note that the PCI layer doesn't put devices into low-power states during the
> > hibernation's "freeze" transition, but drivers can legitimately do that in
> > their "freeze" callbacks which was overlooked in that code and that's what
> > i915 does.]
> > 
> > So IMO what we need is the change below.  I'm going to test it shortly,
> > but please give it a go too.
> 
> So now this looks more reasonable:
> 
>   irq_migrate_all_off_this_cpu: Mask 125 pci_msi_mask_irq+0x0/0x10
>   __pci_write_msi_msg: 0000:00:02.0 00000000fee0100c 0000412a 
>   __pci_write_msi_msg: Not written
>   ...
>   device_pm_callback_start: i915 0000:00:02.0, parent: pci0000:00, noirq bus [thaw]
>   pci_pm_thaw_noirq <-dpm_run_callback
>   __pci_write_msi_msg: 0000:00:02.0 00000000fee0100c 0000412a 
>   device_pm_callback_end: i915 0000:00:02.0, err=0
>   ...
>   resume_irqs: Resume 125
>   ...
>   irq_handler_entry: irq=125 name=i915

Cool.

Let me respin it with a changelog etc then.

Thanks,
Rafael