[U-Boot] U-Boot causes ethernet packet loss under Linux

[Urs Schulz]

Hey there,

I have several issues with the newer U-Boot versions on my Banana Pi.

I recently decided to upgrade some of my Banana Pis to the latest
U-Boot, the last version I had there was 2015.04. Unfortunately the
upgrade to 2017.05 caused weird packet-losses on the ethernet interface
in Linux (took me several days to find out, that it's actually u-boot
causing the problems). When downgrading to my old 2015.04, everythings
works fine.

The packet loss only occurs in low-load situations, for example with
ping or ssh. I have successfully transfered some large files over the
network with netcat without any issues. So maybe it's some
powersaving-issue with Linux. But obviously, keeping the network
interface under full load at all times can't be the right solution to
the problem. About 10-20% of all packets get lost with ping.

So I had hoped, it is some kind of "temporary issue" fixed in the next
version and today decided to try again with a newer version.
Unfortunately 2017.07 has even more issues:

First, the packet-loss issue hasn't disappeared. Sad.

Second, this version is no longer able to turn on the hdmi interface on
the pi but seems to boot the system (after a minute or so it is
"reachable" via network).

The same applies to 2017.09-rc2.


So I thought, the problem is probably caused, because the newer U-Boot
versions turn on the network interface and configure it (and then linux
fails to reconfigure it correctly, or something).

I therefore tried to compile U-Boot 2017.05 without network support:

I disabled CONFIG_CMD_NET in order to disable CONFIG_NET:

> make CROSS_COMPILE=armv7l-linux-gnueabihf- Bananapi_defconfig
> sed -re 's/^CONFIG_NET=y$/CONFIG_NET=n/' \
>     -e 's/^CONFIG_CMD_NET=y$/CONFIG_CMD_NET=n/' -i .config
> make CROSS_COMPILE=armv7l-linux-gnueabihf- oldconfig
> make CROSS_COMPILE=armv7l-linux-gnueabihf- -j6

This caused linker errors:

[...]
  LD      u-boot
board/sunxi/built-in.o: In function `setup_environment':
/tmp/u-boot-2017.05/board/sunxi/board.c:700: undefined reference to `eth_setenv_enetaddr'
armv7l-linux-gnueabihf-ld.bfd: BFD (GNU Binutils) 2.29 assertion fail ../../binutils-2.29/bfd/elf32-arm.c:9509
make: *** [Makefile:1211: u-boot] Error 1


So, some kind of dependency issue. I checked the .config file and found
several more network-related options and disabled all of them:

CONFIG_CMD_DHCP
CONFIG_CMD_PXE
CONFIG_CMD_NFS
CONFIG_CMD_MII
CONFIG_CMD_PING

In order to make this work, I also had to set:
CONFIG_DISTRO_DEFAULTS=n

Then I ran oldconfig again, double checked the .config and tried
compilation again:

[...]
  CC      common/env_common.o
In file included from include/configs/sunxi-common.h:461:0,
                 from include/configs/sun7i.h:28,
                 from include/config.h:5,
                 from include/common.h:21,
                 from common/env_common.c:11:
include/config_distro_bootcmd.h:305:2: error: expected '}' before 'BOOT_TARGET_DEVICES_references_PXE_without_CONFIG_CMD_DHCP_or_PXE'
  BOOT_TARGET_DEVICES_references_PXE_without_CONFIG_CMD_DHCP_or_PXE
  ^
include/config_distro_bootcmd.h:305:2: note: in definition of macro 'BOOTENV_DEV_NAME_PXE'
  BOOT_TARGET_DEVICES_references_PXE_without_CONFIG_CMD_DHCP_or_PXE
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/configs/sunxi-common.h:442:2: note: in expansion of macro 'BOOTENV_DEV_NAME'
  func(PXE, pxe, na) \
  ^~~~
include/config_distro_bootcmd.h:311:18: note: in expansion of macro 'BOOT_TARGET_DEVICES'
  "boot_targets=" BOOT_TARGET_DEVICES(BOOTENV_DEV_NAME) "\0"
                  ^~~~~~~~~~~~~~~~~~~
include/config_distro_bootcmd.h:328:2: note: in expansion of macro 'BOOTENV_BOOT_TARGETS'
  BOOTENV_BOOT_TARGETS \
  ^~~~~~~~~~~~~~~~~~~~
include/configs/sunxi-common.h:515:2: note: in expansion of macro 'BOOTENV'
  BOOTENV
  ^~~~~~~
include/env_default.h:108:2: note: in expansion of macro 'CONFIG_EXTRA_ENV_SETTINGS'
  CONFIG_EXTRA_ENV_SETTINGS
  ^~~~~~~~~~~~~~~~~~~~~~~~~
make[1]: *** [scripts/Makefile.build:281: common/env_common.o] Error 1
make: *** [Makefile:1234: common] Error 2


Now I'm out of ideas. Looks like disabling CONFIG_DISTRO_DEFAULTS was a
step in the wrong direction.

So my questions are:

1. Is there a way to compile U-Boot without networking support?

2. Or is there a way to fix my package-loss problems in Linux (maybe the
problem lies within the kernel, not U-Boot and U-Boot is just triggering
it).

3. How can I enable the HDMI in the latest U-Boot versions (2017.07 and
2017.09-rc2) on the Banana Pi?


Kind regards
    Urs