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

[Niklas Cassel]

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/20251023072217.901888-1-den@xxxxxxxxxxxxx/)

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.)


Kind regards,
Niklas