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.
