On Thu, Sep 28, 2023 at 05:36:30PM -0500, Bjorn Helgaas wrote:
> On Mon, Sep 18, 2023 at 02:48:01PM +0200, Lukas Wunner wrote:
> > struct pci_dev contains two flags which govern whether the device may
> > suspend to D3cold:
> >
> > * no_d3cold provides an opt-out for drivers (e.g. if a device is known
> > to not wake from D3cold)
> >
> > * d3cold_allowed provides an opt-out for user space (default is true,
> > user space may set to false)
> >
> > Since commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend"),
> > the user space setting overwrites the driver setting. Essentially user
> > space is trusted to know better than the driver whether D3cold is
> > working.
> >
> > That feels unsafe and wrong. Assume that the change was introduced
> > inadvertently and do not overwrite no_d3cold when d3cold_allowed is
> > modified. Instead, consider d3cold_allowed in addition to no_d3cold
> > when choosing a suspend state for the device.
> >
> > That way, user space may opt out of D3cold if the driver hasn't, but it
> > may no longer force an opt in if the driver has opted out.
> >
> > Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
> > Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx # v4.8+
> > Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
>
> Mika and Mario, you both commented on this, but I *think* you were
> both OK with it as-is for now? If so, can you give a Reviewed-by?
> I don't want to go ahead if you have any concerns.
No concerns from me,
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
