callback is never called,
uart_suspend_port() and enable_irq_wake() is never called; so the UART
interrupt is masked by check_wakeup_irqs() and the UART can't wake up
the MPU.

The remaining mechanism that could have awakened the system would have
been I/O chain wakeups.  These wouldn't be active because the console
UART's clocks are never disabled when no_console_suspend is used,
preventing the full chip from idling.  Also, current mainline doesn't
yet support full chip idle states for OMAP4, so I/O chain wakeups are
not enabled.

This patch is the result of a collaboration.  John Stultz
<johnstul@us.ibm.com> and Andy Green <andy.green@linaro.org> reported
the serial wakeup problem that led to the discovery of this problem.
Kevin Hilman <khilman@ti.com> narrowed the problem down to the use of
no_console_suspend.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Andy Green <andy.green@linaro.org>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
"®Yº‘9x