Messages in this thread | | | Date | Tue, 10 Oct 2023 11:34:39 -0500 | Subject | Re: [PATCH v2] PCI: Make d3cold_allowed sysfs attribute read only | From | Mario Limonciello <> |
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On 10/10/2023 11:33, Bjorn Helgaas wrote: > On Thu, Oct 05, 2023 at 01:56:27PM -0500, Mario Limonciello wrote: >> On 10/5/2023 13:53, Bjorn Helgaas wrote: >>> On Wed, Oct 04, 2023 at 09:47:31AM -0500, Mario Limonciello wrote: >>>> Before d3cold was stable userspace was allowed to influence the kernel's >>>> decision of whether to enable d3cold for a device by a sysfs file >>>> `d3cold_allowed`. This potentially allows userspace to break the suspend >>>> for the system. >>> >>> Is "Before d3cold was stable" referring to a "d3cold" read-only >>> variable, or to Linux functionality of using D3cold, or ...? >> >> I was referring to the previous thread's comments when I asked about the >> history on it. >> >>> In what sense does the `d3cold_allowed` sysfs file break suspend? >> >> SoCs might not be able to get into their deepest sleep state if userspace >> messes with it. >> >>>> For debugging purposes `pci_port_pm=` can be used to control whether >>>> a PCI port will go into D3cold and runtime PM can be turned off by >>>> sysfs on PCI end points. >>> >>> I guess this should be "pcie_port_pm=", which affects *all* PCIe >>> ports? >> >> Yes. >> >>> Which sysfs file turns off runtime PM for endpoints? >> >> /sys/bus/pci/devices/*/power/control > > To close the loop on this, I think these are questions that should be > answered in the commit log (actually, that's usually the case when I > have questions, because future readers of the git history may have the > same questions, and it's not practical to dig the answers out of the > lore archive). > > Bjorn
OK thanks, sometimes it's unclear if you just want to know more or want it in the commit message.
I'll respin a v2 with the commit message adjusted.
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