Re: [RFC PATCH v2 19/27] PCI: dwc: ep: Cache MSI outbound iATU mapping

[Niklas Cassel]

On Sun, Nov 30, 2025 at 01:03:57AM +0900, Koichiro Den wrote:
> dw_pcie_ep_raise_msi_irq() currently programs an outbound iATU window
> for the MSI target address on every interrupt and tears it down again
> via dw_pcie_ep_unmap_addr().
> 
> On systems that heavily use the AXI bridge interface (for example when
> the integrated eDMA engine is active), this means the outbound iATU
> registers are updated while traffic is in flight. The DesignWare
> endpoint spec warns that updating iATU registers in this situation is
> not supported, and the behavior is undefined.

Please reference a specific section in the EP databook, and the specific
EP databook version that you are using.

This patch appears to address quite a serious issue, so I think that you
should submit it as a standalone patch, and not as part of a series.

(Especially not as part of an RFC which can take quite long before it is
even submitted as a normal (non-RFC) series.)


Kind regards,
Niklas