From: Bjorn Helgaas <bjorn.helgaas@hp.com>

PNP devices can use shared interrupts, so check to see whether we'll need
SA_SHIRQ for request_irq().

The builtin PDH UART on the HP rx8640 is an example of an ACPI/PNP device
that uses a shareable level-triggered, active-low interrupt.  The interrupt
can be shared in very large I/O configurations or by artificially lowering
IA64_DEF_LAST_DEVICE_VECTOR.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Adam Belay <ambx1@neo.rr.com>
Cc: Matthieu Castet <castet.matthieu@free.fr>
Cc: Li Shaohua <shaohua.li@intel.com>
Cc: Len Brown <len.brown@intel.com>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/serial/8250_pnp.c |    2 ++
 1 file changed, 2 insertions(+)

diff -puN drivers/serial/8250_pnp.c~serial-allow-shared-8250_pnp-interrupts drivers/serial/8250_pnp.c
--- a/drivers/serial/8250_pnp.c~serial-allow-shared-8250_pnp-interrupts
+++ a/drivers/serial/8250_pnp.c
@@ -431,6 +431,8 @@ serial_pnp_probe(struct pnp_dev *dev, co
 #endif
 
 	port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
+	if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
+		port.flags |= UPF_SHARE_IRQ;
 	port.uartclk = 1843200;
 	port.dev = &dev->dev;
 
_