of_irq_get() may return a negative error number as well as 0 on failure, while the driver only checks for 0, blithely continuing with the call to irq_set_chained_handler_and_data() -- that function expects *unsigned int* so should probably do nothing when a large IRQ number resulting from a conversion of a negative error number is passed to it. The driver then probes successfully while being only partly functional... Check for 'irq <= 0' instead and propagate the negative error number to the probe method -- that will allow the deferred probing as well... Fixes: d3c68e0a7e34 ("PCI: faraday: Add Faraday Technology FTPCI100 PCI Host Bridge driver") Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> --- drivers/pci/host/pci-ftpci100.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Index: pci/drivers/pci/host/pci-ftpci100.c =================================================================== --- pci.orig/drivers/pci/host/pci-ftpci100.c +++ pci/drivers/pci/host/pci-ftpci100.c @@ -350,9 +350,9 @@ static int faraday_pci_setup_cascaded_ir /* All PCI IRQs cascade off this one */ irq = of_irq_get(intc, 0); - if (!irq) { + if (irq <= 0) { dev_err(p->dev, "failed to get parent IRQ\n"); - return -EINVAL; + return irq ?: -EINVAL; } p->irqdomain = irq_domain_add_linear(intc, 4,