On Tue, 13 Jan 2015, Boris Brezillon wrote:

+	ret = irq_set_handler_data(irq, demux);
+	if (ret) {
+		pr_err("Failed to assign handler data\n");
+		goto err_free_domain;
+	}
+
+	irq_set_chained_handler(irq, irq_dumb_demux_handler);
+
+	/*
+	 * Disable the src irq (automatically enabled by
+	 * irq_set_chained_handler) to prevent irqs from happening while
+	 * nobody requested any of the demuxed irqs.
+	 */
+	disable_irq(irq);

We rather prevent the startup of the irq line right away.

enum {
     IRQ_CHAINED_NONE,
     IRQ_CHAINED_STARTUP,
     IRQ_CHAINED_NOSTARTUP,
};

-__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
-                  const char *name);
+__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int chained_mode,
+                  const char *name);

{
....
        if (handle != handle_bad_irq && chained_mode) {
                irq_settings_set_noprobe(desc);
                irq_settings_set_norequest(desc);
                irq_settings_set_nothread(desc);
-               irq_startup(desc, true);
+               if (chained_mode == IRQ_CHAINED_STARTUP)
+                       irq_startup(desc, true);
	}
....
}

Hmm?

	tglx