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

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:

quoted

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@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---

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 <redacted>

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 ?

Thank you for your help !

-- 
Best regards,
Marek Vasut