Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Mon, 12 Jul 2021 17:30:04 +0200 | Subject | Re: [PATCH][RFT] PCI: Use pci_update_current_state() in pci_enable_device_flags() |
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On Fri, Jul 9, 2021 at 1:21 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Thu, Jul 8, 2021 at 10:34 PM Maximilian Luz <luzmaximilian@gmail.com> wrote: > > > > On 7/8/21 3:25 PM, Rafael J. Wysocki wrote: > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > > > > Updating the current_state field of struct pci_dev the way it is done > > > in pci_enable_device_flags() before calling do_pci_enable_device() may > > > not work. For example, if the given PCI device depends on an ACPI > > > power resource whose _STA method initially returns 0 ("off"), but the > > > config space of the PCI device is accessible and the power state > > > retrieved from the PCI_PM_CTRL register is D0, the current_state > > > field in the struct pci_dev representing that device will get out of > > > sync with the power.state of its ACPI companion object and that will > > > lead to power management issues going forward. > > > > > > To avoid such issues, make pci_enable_device_flags() call > > > pci_update_current_state() which takes ACPI device power management > > > into account, if present, to retrieve the current power state of the > > > device. > > > > > > Link: https://lore.kernel.org/lkml/20210314000439.3138941-1-luzmaximilian@gmail.com/ > > > Reported-by: Maximilian Luz <luzmaximilian@gmail.com> > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > --- > > > > > > Hi Maximilian, > > > > > > Because commit 4514d991d992 ("PCI: PM: Do not read power state in > > > pci_enable_device_flags()"), the issue addressed by it is back, so > > > we need an alternative way to address it. > > > > > > Can you please check if this patch makes that issue go away? > > > > Hi, > > > > just tested this on v5.13 and it works, thanks! Feel free to add > > > > Tested-by: Maximilian Luz <luzmaximilian@gmail.com>
Michael, Salvatore, since this alternative to commit 4514d991d992 works for Maximilian, I'm going to queue it up for 5.15 (barring any objections from Bjorn), so I would appreciate it if you could test it and let me know whether or not there were any problems with it.
The patch can be downloaded from https://patchwork.kernel.org/project/linux-pm/patch/4327888.LvFx2qVVIh@kreacher
Thanks!
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