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ARM: debug: provide dummy default option for DEBUG_LL UART choice

PATCH New Will Deacon 2 participants 2 messages Sep 30, 2011 – Oct 3, 2011 Arm (32-bit)

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Will Deacon

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PATCH 1/1 ARM: debug: provide dummy default option for DEBUG_LL UART choice

Defaulting to DEBUG_ICEDCC will cause systems to hang during boot unless a hardware debugger is listening to the debug comms. channel.

This patch adds a dummy UART option as the default DEBUG_LL choice which requires the platform to do the right thing.

Acked-by Stephen Boyd <[email protected]>
Signed-off-by Will Deacon <[email protected]>

---

This came out of discussion on the list yesterday but I thought I'd better post a patch before sending to Russell.

Will

 arch/arm/Kconfig.debug |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)
arch/arm/Kconfig.debug +10 -2
index 32b1be4..5bc7814 100644
@@ -81,6 +81,14 @@ choice
 	prompt "Kernel low-level debugging port"
 	depends on DEBUG_LL
 
+	config DEBUG_LL_UART_NONE
+		bool "No low-level debugging UART"
+		help
+		  Say Y here if your platform doesn't provide a UART option
+		  below. This relies on your platform choosing the right UART
+		  definition internally in order for low-level debugging to
+		  work.
+
 	config DEBUG_ICEDCC
 		bool "Kernel low-level debugging via EmbeddedICE DCC channel"
 		help

@@ -89,8 +97,8 @@ choice
 		  co-processor 14. This is known to work on the ARM9 style ICE
 		  channel and on the XScale with the PEEDI.
 
-		  It does include a timeout to ensure that the system does not
-		  totally freeze when there is nothing connected to read.
+		  Note that the system will appear to hang during boot if there
+		  is nothing connected to read from the DCC.
 
 	config DEBUG_FOOTBRIDGE_COM1
 		bool "Kernel low-level debugging messages via footbridge 8250 at PCI COM1"
Signature · 1 line
1.7.0.4
#1 lore raw

PATCH 1/1 ARM: debug: provide dummy default option for DEBUG_LL UART choice

Quoted 6 lines · Will Deacon

Defaulting to DEBUG_ICEDCC will cause systems to hang during boot unless a hardware debugger is listening to the debug comms. channel.

This patch adds a dummy UART option as the default DEBUG_LL choice which requires the platform to do the right thing.

Quoted 6 lines
Acked-by Stephen Boyd <[email protected]>
Signed-off-by Will Deacon <[email protected]>

---

This came out of discussion on the list yesterday but I thought I'd better post a patch before sending to Russell.

This fixes my OMAP4 boot problems (where DEBUG_ICEDCC got silently selected). Tested on -next-20110930.

Tested-by Marc Zyngier <[email protected]>
	M.
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