Revision 197234520bd83aba2199add57a9d2678ee7f9781 authored by Paul Walmsley on 26 January 2012, 02:50:56 UTC, committed by Greg Kroah-Hartman on 09 February 2012, 18:48:36 UTC
The receive FIFO wakeup latency estimate in the omap-serial driver is
three orders of magnitude too small.  This effectively prevents the
MPU from going to a low-power state when CONFIG_CPU_IDLE=y.  This is a
major power management regression and masks some other FIFO-related
bugs in the driver.

Fix by correcting the most egregious problem in the RX wakeup latency
estimate.  There are several other flaws in the estimator; these will
be fixed by a separate patch series intended for 3.4.

The difference in low-power states with this patch can be observed via
debugfs in pm_debug/count.

This estimate does not have any effect when CONFIG_CPU_IDLE=n.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Raw File
Kconfig
menuconfig SAMPLES
	bool "Sample kernel code"
	help
	  You can build and test sample kernel code here.

if SAMPLES

config SAMPLE_TRACEPOINTS
	tristate "Build tracepoints examples -- loadable modules only"
	depends on TRACEPOINTS && m
	help
	  This build tracepoints example modules.

config SAMPLE_TRACE_EVENTS
	tristate "Build trace_events examples -- loadable modules only"
	depends on EVENT_TRACING && m
	help
	  This build trace event example modules.

config SAMPLE_KOBJECT
	tristate "Build kobject examples -- loadable modules only"
	depends on m
	help
	  This config option will allow you to build a number of
	  different kobject sample modules showing how to use kobjects,
	  ksets, and ktypes properly.

	  If in doubt, say "N" here.

config SAMPLE_KPROBES
	tristate "Build kprobes examples -- loadable modules only"
	depends on KPROBES && m
	help
	  This build several kprobes example modules.

config SAMPLE_KRETPROBES
	tristate "Build kretprobes example -- loadable modules only"
	default m
	depends on SAMPLE_KPROBES && KRETPROBES

config SAMPLE_HW_BREAKPOINT
	tristate "Build kernel hardware breakpoint examples -- loadable module only"
	depends on HAVE_HW_BREAKPOINT && m
	help
	  This builds kernel hardware breakpoint example modules.

config SAMPLE_KFIFO
	tristate "Build kfifo examples -- loadable modules only"
	depends on m
	help
	  This config option will allow you to build a number of
	  different kfifo sample modules showing how to use the
	  generic kfifo API.

	  If in doubt, say "N" here.

config SAMPLE_KDB
	tristate "Build kdb command example -- loadable modules only"
	depends on KGDB_KDB && m
	help
	  Build an example of how to dynamically add the hello
	  command to the kdb shell.

endif # SAMPLES
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