Re: [PATCH v6 0/8] PCI: endpoint: pci-ep-msi: Add embedded doorbell fallback

On Tue, Feb 10, 2026 at 01:24:29PM +0100, Niklas Cassel wrote:
> On Mon, Feb 09, 2026 at 09:53:08PM +0900, Koichiro Den wrote:
> > Tested on
> > =========
> > 
> > I tested the embedded (DMA) doorbell fallback path (via pci-epf-test) on
> > R-Car Spider boards:
> > 
> >   $ ./pci_endpoint_test -t DOORBELL_TEST
> >   TAP version 13
> >   1..1
> >   # Starting 1 tests from 1 test cases.
> >   #  RUN           pcie_ep_doorbell.DOORBELL_TEST ...
> >   #            OK  pcie_ep_doorbell.DOORBELL_TEST
> >   ok 1 pcie_ep_doorbell.DOORBELL_TEST
> >   # PASSED: 1 / 1 tests passed.
> >   # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
> > 
> > with the following message observed on the EP side:
> > 
> >   [   80.464653] pci_epf_test pci_epf_test.0: Using embedded (DMA) doorbell fallback
> > 
> > (Note: for the test to pass on R-Car Spider, one of the following was required:
> >  - echo 1048576 > functions/pci_epf_test/func1/pci_epf_test.0/bar2_size
> >  - apply https://lore.kernel.org/all/[email protected]/)
> 
> I applied this series on top of branch pci/controller/dwc
> on Rock 5B (pcie-dw-rockchip.c).
> 
> On EP side:
> [   39.218533] pci_epf_test pci_epf_test.0: Can't find MSI domain for EPC
> [   39.219125] pci_epf_test pci_epf_test.0: Using embedded (DMA) doorbell fallback
> 
> On RC side:
> #  RUN           pcie_ep_doorbell.DOORBELL_TEST ...
> [   40.297892] pci-endpoint-test 0000:01:00.0: Failed to trigger doorbell in endpoint
> # pci_endpoint_test.c:279:DOORBELL_TEST:Expected 0 (0) == ret (-22)
> # pci_endpoint_test.c:279:DOORBELL_TEST:Test failed for Doorbell
> 
> # DOORBELL_TEST: Test failed
> #          FAIL  pcie_ep_doorbell.DOORBELL_TEST
> not ok 23 pcie_ep_doorbell.DOORBELL_TEST
> 
> Any suggestions?
> 
> (All BARs in pcie-dw-rockchip.c is marked as BAR_RESIZABLE.)

Thank you for testing.

If the failure was observed in a scenario other than a plain
`./pci_endpoint_test -t DOORBELL_TEST`, could you please try again with [1]
applied as well?

[1] https://lore.kernel.org/linux-pci/[email protected]/

Best regards,
Koichiro

> 
> 
> Kind regards,
> Niklas
>