Re: [PATCH v3] PCI: rcar-gen4: Add missing PM ops

[Koichiro Den]

On Tue, Sep 08, 2026 at 06:29:24PM +0200, Marek Vasut wrote:
> Hello Den-san,
> 
> On 9/8/26 3:05 AM, Koichiro Den wrote:
> > On Mon, Sep 07, 2026 at 06:35:22PM +0200, Marek Vasut wrote:
> > > The R-Car Gen4 PCIe controller is part of a power domain. On R-Car S4
> > > and V4H, this is an always-on power domain which is not shut down in
> > > suspend. On R-Car V4M, this is a dedicated A2PCIPHY power domain,
> > > which is shut down during suspend, and the controller loses state,
> > > which prevents the PCIe from working after resume.
> > > 
> > > Fix this by adding generic suspend/resume noirq ops for the controller,
> > > which tear the link down on suspend, and restart it on resume. Use the
> > > same PM ops on all of R-Car Gen4 to gracefully suspend and resume the
> > > PCIe link on V4H and S4 too.
> > > 
> > > Test case which demonstrates the problem on R-Car V4M:
> > > "
> > > $ hexdump -vC /sys/bus/pci/devices/0000:00:00.0/config > /tmp/pre
> > > $ echo s2idle > /sys/power/mem_sleep
> > > $ echo platform > /sys/power/pm_test
> > > $ echo mem > /sys/power/state
> > > $ hexdump -vC /sys/bus/pci/devices/0000:00:00.0/config > /tmp/post
> > > $ diff -Naru /tmp/pre /tmp/post
> > > ...
> > > -00000000  12 19 32 00 07 05 10 00  00 00 04 06 00 00 01 00
> > > +00000000  12 19 32 00 07 05 10 00  00 00 00 ff 00 00 80 00
> > >                                            ^^^^^
> > >                                      Class 0604->00ff
> > > "
> > > 
> > > Fixes: 0d0c551011df ("PCI: rcar-gen4: Add R-Car Gen4 PCIe controller support for host mode")
> > > Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > > Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > > Reported-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > > Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxxxx>
> > > ---
> > 
> > The s2idle test with pm_test=platform now passes in EP mode on S4 Spider even
> > with CONFIG_PCIE_DW_HOST=y. Thanks! Feel free to use the tag for it if it helps.
> > 
> > Tested-by: Koichiro Den <den@xxxxxxxxxxxxx>
> Thank you for your test. I would like to ask -- is the EP side of PCIe link
> behaving correctly during suspend/resume cycle on your S4 setup ? Does the
> EP require any special handling during suspend/resume ?

To be clear, what I confirmed was the following:

- The panic I observed with v1 no longer occurs with this newer revision.
- I could create a vNTB EPF after running the test.
- With vNTB/ntb_netdev already connected before the test. ping resumed normally
  afterwards.

Note: I used the suspend test from the commit message on the EP:
  echo s2idle > /sys/power/mem_sleep && \
  echo platform > /sys/power/pm_test && \
  echo mem > /sys/power/state

Based on these, I believe this patch introduces no regression in EP mode on S4.
Any pre-existing EP suspend/resume issues could be addressed separately.

Best regards,
Koichiro

> 
> Thank you for your help !
> 
> -- 
> Best regards,
> Marek Vasut