On Tue, Jun 28, 2011 at 9:57 PM, Will Deacon [off-list ref] wrote:

Hi Bryan,

On Tue, Jun 28, 2011 at 02:37:45PM +0100, Bryan Wu wrote:

quoted

For our Ubuntu kernel on OMAP4 machine, we need to enable OMAP3 as well as
OMAP4. OMAP3_EMU has to be enabled manully to make CPU_HAS_PMU=y, which is
required by perf.

So this patch will select the OMAP3_EMU if ARCH_OMAP3 is enabled.

Cc: Ming Lei <redacted>
Signed-off-by: Bryan Wu <redacted>
---
?arch/arm/Kconfig | ? ?4 ++--
?1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2fd0911..53d0eba 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig

@@ -1084,10 +1084,10 @@ config XSCALE_PMU

? ? ? default y

?config CPU_HAS_PMU
- ? ? depends on (CPU_V6 || CPU_V6K || CPU_V7 || XSCALE_PMU) && \
- ? ? ? ? ? ? ? ?(!ARCH_OMAP3 || OMAP3_EMU)
+ ? ? depends on CPU_V6 || CPU_V6K || CPU_V7 || XSCALE_PMU
? ? ? default y
? ? ? bool
+ ? ? select OMAP3_EMU if ARCH_OMAP3

?config MULTI_IRQ_HANDLER
? ? ? bool

This issue has been discussed on the list in the past and I still think that
it would be better for your config to select OMAP3_EMU explicitly. If we do
that here unconditionally then we end up also bringing in OC_ETM which isn't
something that sounds like a good idea (may have implications for power
consumption in production hardware?).

Will,

I quite understand your concern. How about this one?
----

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2fd0911..e53f9e4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig

@@ -1084,10 +1084,10 @@ config XSCALE_PMU
        default y

 config CPU_HAS_PMU
-       depends on (CPU_V6 || CPU_V6K || CPU_V7 || XSCALE_PMU) && \
-                  (!ARCH_OMAP3 || OMAP3_EMU)
+       depends on CPU_V6 || CPU_V6K || CPU_V7 || XSCALE_PMU
        default y
        bool
+       select OMAP3_EMU if (PERF_EVENTS && ARCH_OMAP3)

 config MULTI_IRQ_HANDLER
        bool

----

I think it is quite logically clear.
1. if the CPU is V6, V6K, V7, then CPU_HAS_PMU supported
2. if the CPU is OMAP3, we need select OMAP3_EMU built-in
3. if we don't use PERF at all, we don't need built-in OMAP3_EMU

Thanks,
-- 
Bryan Wu [off-list ref]
Kernel Developer ? ?+86.138-1617-6545 Mobile
Ubuntu Kernel Team
Canonical Ltd. ? ? ?www.canonical.com
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