Re: [PATCH v4] PCI: dw-rockchip: Move the INTx irq setup to probe

[Niklas Cassel <cassel@kernel.org>]

On Thu, Sep 24, 2026 at 12:06:33PM +0800, Shawn Lin wrote:
> Since commit b376b3ff9cb0 ("PCI: dw-rockchip: Implement .reset_root_port()
> and use for link down"), .reset_root_port() re-runs the host ops .init()
> callback to reprogram the Root Complex after a controller reset. That
> works for the register programming, but .init() is not re-entrant: it
> also creates the INTx irq domain and installs the chained INTx handler.
> Every root port reset therefore ends up with a second irq domain
> registered for the same fwnode: the previous one is leaked, as it is
> never removed, and worse, the INTx virqs of the downstream PCI devices
> were allocated in the previous irq domain and are never re-mapped, while
> the chained handler now looks up virqs in the new, empty domain. After a
> link down recovery, INTx interrupts are silently lost.
> 
> Fix it by moving the of_irq_get_byname() lookup, the INTx irq domain
> creation and the chained handler installation out of .init() and into
> rockchip_pcie_configure_rc(), just before dw_pcie_host_init(). The
> lookup has to happen before the host is initialized, because
> dw_pcie_host_init() enumerates the bus and probes the downstream
> devices, and pci_assign_irq() maps their INTx interrupts at that point:
> if the domain does not exist yet, the mapping fails and the devices end
> up without a usable INTx. This also mirrors how the qcom driver requests
> its global IRQ, and leaves .init() with nothing but idempotent register
> programming, so both .reset_root_port() and dw_pcie_resume_noirq() can
> safely re-run it. Re-running of_irq_get_byname() on every resume is also
> gone.
> 
> Fixes: b376b3ff9cb0 ("PCI: dw-rockchip: Implement .reset_root_port() and use for link down")
> Suggested-by: Niklas Cassel <cassel@kernel.org>
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

Reviewed-by: Niklas Cassel <cassel@kernel.org>