[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Luca Ceresoli]

The current Buildroot defconfigs for Raspberry Pi and Raspberry Pi 2
instantiate a console on tty1, which appears on HDMI. Add a console on
the serial port (ttyAMA0) to be more consistent with other defconfigs
and provide a better out-of-the-box experience to users used to have a
serial console from Buildroot defconfigs.

This requires two changes:
 1. have two 'console=' entries in the kernel command line;
 2. add a new getty process to the generated inittab.

Step 2 requires a post-build script since the Buildroot makefiles can
configure only one console. But instead of simply adding a new getty
on ttyAMA0 (which would work) this patch actually changes
BR2_TARGET_GENERIC_GETTY_PORT from tty1 to ttyAMA0, then adds back
tty1 via post-build.sh. This is done only to avoid the
"GENERIC_SERIAL" comment where we instantiate an HDMI console, then
instantiate a really-serial console on another line.

The result is these two inittab lines:

  ttyAMA0::respawn:/sbin/getty -L  ttyAMA0 0 vt100 # GENERIC_SERIAL
  tty1::respawn:/sbin/getty -L  tty1 0 vt100 # HDMI console

Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>

---

Tested on both Raspberry Pi B and Raspberry Pi 2, each on serial and
HDMI console.
---
 board/raspberrypi/post-build.sh  | 9 +++++++++
 configs/raspberrypi2_defconfig   | 3 ++-
 configs/raspberrypi_defconfig    | 3 ++-
 package/rpi-firmware/cmdline.txt | 2 +-
 4 files changed, 14 insertions(+), 3 deletions(-)
 create mode 100755 board/raspberrypi/post-build.sh

diff --git a/board/raspberrypi/post-build.sh b/board/raspberrypi/post-build.sh
new file mode 100755
index 000000000000..7eae14a88569
--- /dev/null
+++ b/board/raspberrypi/post-build.sh
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+set -u
+set -e
+
+# Add a console on tty1
+grep -qE '^tty1::' ${TARGET_DIR}/etc/inittab || \
+sed -i '/GENERIC_SERIAL/a\
+tty1::respawn:/sbin/getty -L  tty1 0 vt100 # HDMI console' ${TARGET_DIR}/etc/inittab
diff --git a/configs/raspberrypi2_defconfig b/configs/raspberrypi2_defconfig
index ce41ee31adba..0ffc6cdaf158 100644
--- a/configs/raspberrypi2_defconfig
+++ b/configs/raspberrypi2_defconfig
@@ -5,7 +5,7 @@ BR2_ARM_FPU_NEON_VFPV4=y
 
 BR2_TOOLCHAIN_BUILDROOT_CXX=y
 
-BR2_TARGET_GENERIC_GETTY_PORT="tty1"
+BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
 
 # Linux headers same as kernel, a 4.1 series
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_1=y
@@ -33,4 +33,5 @@ BR2_PACKAGE_HOST_MTOOLS=y
 BR2_TARGET_ROOTFS_EXT2=y
 BR2_TARGET_ROOTFS_EXT2_4=y
 # BR2_TARGET_ROOTFS_TAR is not set
+BR2_ROOTFS_POST_BUILD_SCRIPT="board/raspberrypi2/post-build.sh"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="board/raspberrypi2/post-image.sh"
diff --git a/configs/raspberrypi_defconfig b/configs/raspberrypi_defconfig
index 3b3cc504c2be..717d798b3851 100644
--- a/configs/raspberrypi_defconfig
+++ b/configs/raspberrypi_defconfig
@@ -2,7 +2,7 @@ BR2_arm=y
 BR2_arm1176jzf_s=y
 BR2_ARM_EABIHF=y
 
-BR2_TARGET_GENERIC_GETTY_PORT="tty1"
+BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
 
 # Linux headers same as kernel, a 4.1 series
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_1=y
@@ -32,4 +32,5 @@ BR2_PACKAGE_HOST_MTOOLS=y
 BR2_TARGET_ROOTFS_EXT2=y
 BR2_TARGET_ROOTFS_EXT2_4=y
 # BR2_TARGET_ROOTFS_TAR is not set
+BR2_ROOTFS_POST_BUILD_SCRIPT="board/raspberrypi/post-build.sh"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="board/raspberrypi/post-image.sh"
diff --git a/package/rpi-firmware/cmdline.txt b/package/rpi-firmware/cmdline.txt
index 38aa3782621b..155a54693bff 100644
--- a/package/rpi-firmware/cmdline.txt
+++ b/package/rpi-firmware/cmdline.txt
@@ -1 +1 @@
-root=/dev/mmcblk0p2 rootwait
+root=/dev/mmcblk0p2 rootwait console=tty1 console=ttyAMA0,115200
-- 
1.9.1

[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Alexander Dahl]

Hei hei,

Am 2016-03-29 00:08, schrieb Luca Ceresoli:
> The current Buildroot defconfigs for Raspberry Pi and Raspberry Pi 2
> instantiate a console on tty1, which appears on HDMI. Add a console on
> the serial port (ttyAMA0) to be more consistent with other defconfigs
> and provide a better out-of-the-box experience to users used to have a
> serial console from Buildroot defconfigs.

I ran in the very problem last week. So +1 for the idea.

> This requires two changes:
>  1. have two 'console=' entries in the kernel command line;
>  2. add a new getty process to the generated inittab.

Then why not split up those two changes in two patches? ;-)

> -BR2_TARGET_GENERIC_GETTY_PORT="tty1"
> +BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"

+1

> diff --git a/package/rpi-firmware/cmdline.txt b/package/rpi-firmware/cmdline.txt
> index 38aa3782621b..155a54693bff 100644
> --- a/package/rpi-firmware/cmdline.txt
> +++ b/package/rpi-firmware/cmdline.txt
> @@ -1 +1 @@
> -root=/dev/mmcblk0p2 rootwait
> +root=/dev/mmcblk0p2 rootwait console=tty1 console=ttyAMA0,115200

+1

Not sure about the post build script though, maybe someone with more
experience in buildroot could comment on that.

Greets
Alex

-- 
?With the first link, the chain is forged. The first speech censured,
the first thought forbidden, the first freedom denied, chains us all
irrevocably.? (Jean-Luc Picard, quoting Judge Aaron Satie)
*** GnuPG-FP: C28E E6B9 0263 95CF 8FAF  08FA 34AD CD00 7221 5CC6 ***

[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Luca Ceresoli]

Hei hei Alexander,

thanks for your review! See below by replies.

However, when replying to a mail on the mailing list, please reply to
all. This helps involved people to follow the discussion. Typically an
e-mail sent directly is seen sooner that one on a mailing list only.

On 29/03/2016 13:30, Alexander Dahl wrote:
> Hei hei,
> 
> Am 2016-03-29 00:08, schrieb Luca Ceresoli:
>> The current Buildroot defconfigs for Raspberry Pi and Raspberry Pi 2
>> instantiate a console on tty1, which appears on HDMI. Add a console on
>> the serial port (ttyAMA0) to be more consistent with other defconfigs
>> and provide a better out-of-the-box experience to users used to have a
>> serial console from Buildroot defconfigs.
> 
> I ran in the very problem last week. So +1 for the idea.
> 
>> This requires two changes:
>>  1. have two 'console=' entries in the kernel command line;
>>  2. add a new getty process to the generated inittab.
> 
> Then why not split up those two changes in two patches? ;-)

Because change 1 alone is almost useless. It just outputs kernel booting
and early init messages on UART, but no console. I see adding a UART
console as a self-contained change, but of course that's only my opinion.

> 
>> -BR2_TARGET_GENERIC_GETTY_PORT="tty1"
>> +BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
> 
> +1
> 
>> diff --git a/package/rpi-firmware/cmdline.txt b/package/rpi-firmware/cmdline.txt
>> index 38aa3782621b..155a54693bff 100644
>> --- a/package/rpi-firmware/cmdline.txt
>> +++ b/package/rpi-firmware/cmdline.txt
>> @@ -1 +1 @@
>> -root=/dev/mmcblk0p2 rootwait
>> +root=/dev/mmcblk0p2 rootwait console=tty1 console=ttyAMA0,115200
> 
> +1
> 
> Not sure about the post build script though, maybe someone with more
> experience in buildroot could comment on that.

That's OK if you don't feel confident enough to give your official
Acked-by or Reviewed-by tag. Still, you can test the patch on a real
board and report back the outcome. If it works, you can add your
Tested-by tag. Otherwise, please report what went wrong. More details on:

http://nightly.buildroot.org/manual.html#_reviewing_and_testing_patches

Cheers,
-- 
Luca

[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Alexander Dahl]

Hei hei,

On 29.03.2016 16:12, Luca Ceresoli wrote:
> However, when replying to a mail on the mailing list, please reply to
> all. This helps involved people to follow the discussion. Typically an
> e-mail sent directly is seen sooner that one on a mailing list only.

Well, I try to remember it, each community handles this different and I
find it annoying to receive mails twice personally. Some mailing list
filter this, others not. ;-)

> That's OK if you don't feel confident enough to give your official
> Acked-by or Reviewed-by tag. Still, you can test the patch on a real
> board and report back the outcome. If it works, you can add your
> Tested-by tag. Otherwise, please report what went wrong. More details on:

Yeah I actually tried to this evening, but there was a showstopper I
filed a bug for now: https://bugs.busybox.net/show_bug.cgi?id=8831

Maybe I try again later.

Greets
Alex


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[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Arnout Vandecappelle]

On 03/29/16 23:04, Alexander Dahl wrote:
> Hei hei,
>
> On 29.03.2016 16:12, Luca Ceresoli wrote:
>> However, when replying to a mail on the mailing list, please reply to
>> all. This helps involved people to follow the discussion. Typically an
>> e-mail sent directly is seen sooner that one on a mailing list only.
>
> Well, I try to remember it, each community handles this different and I
> find it annoying to receive mails twice personally. Some mailing list
> filter this, others not. ;-)
>
>> That's OK if you don't feel confident enough to give your official
>> Acked-by or Reviewed-by tag. Still, you can test the patch on a real
>> board and report back the outcome. If it works, you can add your
>> Tested-by tag. Otherwise, please report what went wrong. More details on:
>
> Yeah I actually tried to this evening, but there was a showstopper I
> filed a bug for now: https://bugs.busybox.net/show_bug.cgi?id=8831

  But that problem has nothing to do with this patch. I expect that if you 
revert the patch, your build will still fail.

  Regards,
  Arnout


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF

[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Arnout Vandecappelle]

On 03/29/16 00:08, Luca Ceresoli wrote:
> The current Buildroot defconfigs for Raspberry Pi and Raspberry Pi 2
> instantiate a console on tty1, which appears on HDMI. Add a console on
> the serial port (ttyAMA0) to be more consistent with other defconfigs
> and provide a better out-of-the-box experience to users used to have a
> serial console from Buildroot defconfigs.
>
> This requires two changes:
>   1. have two 'console=' entries in the kernel command line;
>   2. add a new getty process to the generated inittab.
>
> Step 2 requires a post-build script since the Buildroot makefiles can
> configure only one console. But instead of simply adding a new getty
> on ttyAMA0 (which would work) this patch actually changes
> BR2_TARGET_GENERIC_GETTY_PORT from tty1 to ttyAMA0, then adds back
> tty1 via post-build.sh. This is done only to avoid the
> "GENERIC_SERIAL" comment where we instantiate an HDMI console, then
> instantiate a really-serial console on another line.
>
> The result is these two inittab lines:
>
>    ttyAMA0::respawn:/sbin/getty -L  ttyAMA0 0 vt100 # GENERIC_SERIAL
>    tty1::respawn:/sbin/getty -L  tty1 0 vt100 # HDMI console
>
> Cc: Yann E. MORIN <yann.morin.1998@free.fr>
> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
>
> ---
>
> Tested on both Raspberry Pi B and Raspberry Pi 2, each on serial and
> HDMI console.
> ---
>   board/raspberrypi/post-build.sh  | 9 +++++++++
>   configs/raspberrypi2_defconfig   | 3 ++-
>   configs/raspberrypi_defconfig    | 3 ++-
>   package/rpi-firmware/cmdline.txt | 2 +-
>   4 files changed, 14 insertions(+), 3 deletions(-)
>   create mode 100755 board/raspberrypi/post-build.sh
>
> diff --git a/board/raspberrypi/post-build.sh b/board/raspberrypi/post-build.sh
> new file mode 100755
> index 000000000000..7eae14a88569
> --- /dev/null
> +++ b/board/raspberrypi/post-build.sh
> @@ -0,0 +1,9 @@
> +#!/bin/sh
> +
> +set -u
> +set -e
> +
> +# Add a console on tty1
> +grep -qE '^tty1::' ${TARGET_DIR}/etc/inittab || \
> +sed -i '/GENERIC_SERIAL/a\
> +tty1::respawn:/sbin/getty -L  tty1 0 vt100 # HDMI console' ${TARGET_DIR}/etc/inittab
> diff --git a/configs/raspberrypi2_defconfig b/configs/raspberrypi2_defconfig
> index ce41ee31adba..0ffc6cdaf158 100644
> --- a/configs/raspberrypi2_defconfig
> +++ b/configs/raspberrypi2_defconfig
> @@ -5,7 +5,7 @@ BR2_ARM_FPU_NEON_VFPV4=y
>
>   BR2_TOOLCHAIN_BUILDROOT_CXX=y
>
> -BR2_TARGET_GENERIC_GETTY_PORT="tty1"
> +BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"

  Why not keep the default "console"? That should work, no? Or doesn't that work 
if there are two consoles?


  Regards,
  Arnout


>
>   # Linux headers same as kernel, a 4.1 series
>   BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_1=y
> @@ -33,4 +33,5 @@ BR2_PACKAGE_HOST_MTOOLS=y
>   BR2_TARGET_ROOTFS_EXT2=y
>   BR2_TARGET_ROOTFS_EXT2_4=y
>   # BR2_TARGET_ROOTFS_TAR is not set
> +BR2_ROOTFS_POST_BUILD_SCRIPT="board/raspberrypi2/post-build.sh"
>   BR2_ROOTFS_POST_IMAGE_SCRIPT="board/raspberrypi2/post-image.sh"
> diff --git a/configs/raspberrypi_defconfig b/configs/raspberrypi_defconfig
> index 3b3cc504c2be..717d798b3851 100644
> --- a/configs/raspberrypi_defconfig
> +++ b/configs/raspberrypi_defconfig
> @@ -2,7 +2,7 @@ BR2_arm=y
>   BR2_arm1176jzf_s=y
>   BR2_ARM_EABIHF=y
>
> -BR2_TARGET_GENERIC_GETTY_PORT="tty1"
> +BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"

>
>   # Linux headers same as kernel, a 4.1 series
>   BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_1=y
> @@ -32,4 +32,5 @@ BR2_PACKAGE_HOST_MTOOLS=y
>   BR2_TARGET_ROOTFS_EXT2=y
>   BR2_TARGET_ROOTFS_EXT2_4=y
>   # BR2_TARGET_ROOTFS_TAR is not set
> +BR2_ROOTFS_POST_BUILD_SCRIPT="board/raspberrypi/post-build.sh"
>   BR2_ROOTFS_POST_IMAGE_SCRIPT="board/raspberrypi/post-image.sh"
> diff --git a/package/rpi-firmware/cmdline.txt b/package/rpi-firmware/cmdline.txt
> index 38aa3782621b..155a54693bff 100644
> --- a/package/rpi-firmware/cmdline.txt
> +++ b/package/rpi-firmware/cmdline.txt
> @@ -1 +1 @@
> -root=/dev/mmcblk0p2 rootwait
> +root=/dev/mmcblk0p2 rootwait console=tty1 console=ttyAMA0,115200
>


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF

[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Luca Ceresoli]

Dear Arnout,

On 29/03/2016 22:32, Arnout Vandecappelle wrote:
> On 03/29/16 00:08, Luca Ceresoli wrote:
>> The current Buildroot defconfigs for Raspberry Pi and Raspberry Pi 2
>> instantiate a console on tty1, which appears on HDMI. Add a console on
>> the serial port (ttyAMA0) to be more consistent with other defconfigs
>> and provide a better out-of-the-box experience to users used to have a
>> serial console from Buildroot defconfigs.
>>
>> This requires two changes:
>>   1. have two 'console=' entries in the kernel command line;
>>   2. add a new getty process to the generated inittab.
>>
>> Step 2 requires a post-build script since the Buildroot makefiles can
>> configure only one console. But instead of simply adding a new getty
>> on ttyAMA0 (which would work) this patch actually changes
>> BR2_TARGET_GENERIC_GETTY_PORT from tty1 to ttyAMA0, then adds back
>> tty1 via post-build.sh. This is done only to avoid the
>> "GENERIC_SERIAL" comment where we instantiate an HDMI console, then
>> instantiate a really-serial console on another line.
>>
>> The result is these two inittab lines:
>>
>>    ttyAMA0::respawn:/sbin/getty -L  ttyAMA0 0 vt100 # GENERIC_SERIAL
>>    tty1::respawn:/sbin/getty -L  tty1 0 vt100 # HDMI console
>>
>> Cc: Yann E. MORIN <yann.morin.1998@free.fr>
>> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
>>
>> ---
>>
>> Tested on both Raspberry Pi B and Raspberry Pi 2, each on serial and
>> HDMI console.
>> ---
>>   board/raspberrypi/post-build.sh  | 9 +++++++++
>>   configs/raspberrypi2_defconfig   | 3 ++-
>>   configs/raspberrypi_defconfig    | 3 ++-
>>   package/rpi-firmware/cmdline.txt | 2 +-
>>   4 files changed, 14 insertions(+), 3 deletions(-)
>>   create mode 100755 board/raspberrypi/post-build.sh
>>
>> diff --git a/board/raspberrypi/post-build.sh
>> b/board/raspberrypi/post-build.sh
>> new file mode 100755
>> index 000000000000..7eae14a88569
>> --- /dev/null
>> +++ b/board/raspberrypi/post-build.sh
>> @@ -0,0 +1,9 @@
>> +#!/bin/sh
>> +
>> +set -u
>> +set -e
>> +
>> +# Add a console on tty1
>> +grep -qE '^tty1::' ${TARGET_DIR}/etc/inittab || \
>> +sed -i '/GENERIC_SERIAL/a\
>> +tty1::respawn:/sbin/getty -L  tty1 0 vt100 # HDMI console'
>> ${TARGET_DIR}/etc/inittab
>> diff --git a/configs/raspberrypi2_defconfig
>> b/configs/raspberrypi2_defconfig
>> index ce41ee31adba..0ffc6cdaf158 100644
>> --- a/configs/raspberrypi2_defconfig
>> +++ b/configs/raspberrypi2_defconfig
>> @@ -5,7 +5,7 @@ BR2_ARM_FPU_NEON_VFPV4=y
>>
>>   BR2_TOOLCHAIN_BUILDROOT_CXX=y
>>
>> -BR2_TARGET_GENERIC_GETTY_PORT="tty1"
>> +BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
> 
>  Why not keep the default "console"? That should work, no? Or doesn't
> that work if there are two consoles?

What improvement you expect from using "console" instead of "ttyAMA0"?

OTOH I think ttyAMA0 or tty1 is explicit about the device to use. And as
Yann pointed out on IRC, "console is not a controlling tty, so no Ctrl-C
for example".

-- 
Luca

[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Arnout Vandecappelle]

On 03/29/16 23:56, Luca Ceresoli wrote:
> Dear Arnout,
>
> On 29/03/2016 22:32, Arnout Vandecappelle wrote:
>> On 03/29/16 00:08, Luca Ceresoli wrote:
[snip]
>>> diff --git a/configs/raspberrypi2_defconfig
>>> b/configs/raspberrypi2_defconfig
>>> index ce41ee31adba..0ffc6cdaf158 100644
>>> --- a/configs/raspberrypi2_defconfig
>>> +++ b/configs/raspberrypi2_defconfig
>>> @@ -5,7 +5,7 @@ BR2_ARM_FPU_NEON_VFPV4=y
>>>
>>>    BR2_TOOLCHAIN_BUILDROOT_CXX=y
>>>
>>> -BR2_TARGET_GENERIC_GETTY_PORT="tty1"
>>> +BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
>>
>>   Why not keep the default "console"? That should work, no? Or doesn't
>> that work if there are two consoles?
>
> What improvement you expect from using "console" instead of "ttyAMA0"?
>
> OTOH I think ttyAMA0 or tty1 is explicit about the device to use. And as
> Yann pointed out on IRC, "console is not a controlling tty, so no Ctrl-C
> for example".

  For the record, as concluded on IRC:

- "console" is still a controlling tty, it is init=/bin/sh that doesn't give a 
controlling tty;

- GETTY_PORT="console" will launch a getty on the last console= given on the 
kernel command line

- What I actually meant is that BR2_TARGET_GENERIC_GETTY_PORT can be removed 
completely from the defconfig (as is the case already in roughly half our 
defconfigs) because it anyway defaults to "console".


  Regards,
  Arnout


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF

[Buildroot] [PATCH] raspberrypi, raspberrypi2: add a serial console

[Luca Ceresoli]

Dear Arnout,

On 30/03/2016 00:46, Arnout Vandecappelle wrote:
> On 03/29/16 23:56, Luca Ceresoli wrote:
>> Dear Arnout,
>>
>> On 29/03/2016 22:32, Arnout Vandecappelle wrote:
>>> On 03/29/16 00:08, Luca Ceresoli wrote:
> [snip]
>>>> diff --git a/configs/raspberrypi2_defconfig
>>>> b/configs/raspberrypi2_defconfig
>>>> index ce41ee31adba..0ffc6cdaf158 100644
>>>> --- a/configs/raspberrypi2_defconfig
>>>> +++ b/configs/raspberrypi2_defconfig
>>>> @@ -5,7 +5,7 @@ BR2_ARM_FPU_NEON_VFPV4=y
>>>>
>>>>    BR2_TOOLCHAIN_BUILDROOT_CXX=y
>>>>
>>>> -BR2_TARGET_GENERIC_GETTY_PORT="tty1"
>>>> +BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
>>>
>>>   Why not keep the default "console"? That should work, no? Or doesn't
>>> that work if there are two consoles?
>>
>> What improvement you expect from using "console" instead of "ttyAMA0"?
>>
>> OTOH I think ttyAMA0 or tty1 is explicit about the device to use. And as
>> Yann pointed out on IRC, "console is not a controlling tty, so no Ctrl-C
>> for example".
> 
>  For the record, as concluded on IRC:
> 
> - "console" is still a controlling tty, it is init=/bin/sh that doesn't
> give a controlling tty;
> 
> - GETTY_PORT="console" will launch a getty on the last console= given on
> the kernel command line
> 
> - What I actually meant is that BR2_TARGET_GENERIC_GETTY_PORT can be
> removed completely from the defconfig (as is the case already in roughly
> half our defconfigs) because it anyway defaults to "console".

Thanks for the recap. Will do in v2.

-- 
Luca