Revert "ACPI: Make ACPI interrupt threaded"

This reverts commit 6fe0d062.

Paul bisected this regression.

The conversion was done blindly and is wrong, as it does not provide a
primary handler to disable the level type irq on the device level.
Neither does it set the IRQF_ONESHOT flag which handles that at the irq
line level.  This can't be done as the interrupt might be shared, though
we might extend the core to force it.

So an interrupt on this line will wake up the thread, but immediately
unmask the irq after that.  Due to the interrupt being level type the
hardware interrupt is raised over and over and prevents the irq thread
from handling it.  Fail.

request_irq() unfortunately does not refuse such a request and the patch
was obviously never tested with real interrupts.
Bisected-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/acpi/osl.c

@@ -607,8 +607,7 @@ acpi_os_install_interrupt_handler(u32 gsi, acpi_osd_handler handler,
 
 	acpi_irq_handler = handler;
 	acpi_irq_context = context;
-	if (request_threaded_irq(irq, NULL, acpi_irq, IRQF_SHARED, "acpi",
-				 acpi_irq)) {
+	if (request_irq(irq, acpi_irq, IRQF_SHARED, "acpi", acpi_irq)) {
 		printk(KERN_ERR PREFIX "SCI (IRQ%d) allocation failed\n", irq);
 		acpi_irq_handler = NULL;
 		return AE_NOT_ACQUIRED;