On 05/01/2015 03:56 PM, Dennis Gilmore wrote:
> I have to take this back, it seems that this build is appending:
> " console=ttyS0,115200"
> To the kernel cmdline, I've just double-checked and this is not upstream
> behavior, is this being done by Fedora specific patches ?
> This breaks kernel output and systemd status messages output on
> tty0 / the hdmi output, resulting in a blackscreen until gdm
> As discussed a while back, the proper way to do is set
> stdout-path in the devicetree to the serial console, then the
> kernel will automatically make it a second console, next to tty0
> and output messages on both, and systemd will output messages
> and spawn gettys on both too.
This in my testing is not working unless i add console=ttySO,115200 to the
bootargs I get nothing out at all on the serial port, though in u-boot it had
stdin as serial and stdout as vga. what are all the possible options and how
should things just work? the current patch is not a regression for Fedora. I
want to make things just work for all.
> Upstream u-boot is already setting stdout-path for all sunxi
> devices, so from a sunxi pov the appending of " console=ttyS0,115200"
> is a regression. If this is done for some other boards, it would
> be better to either patch those boards dts files to set stdout-path,
> or u-boot to set stdout-path rather then appending " console=ttyS0,115200"
> and breaking video output. If you can tell me which specific boards
> need work here I can whip up a patch (for others to test).
We should patch all boards to be the same. but it needs to work.
The sunxi boards have a line like this in their upstream include/configs/board.h file:
#define OF_STDOUT_PATH "/soc/serial@07000000:115200"
With the correct version of that present and using a 4.0 kernel you should
get output on both the serial console and a vga/hdmi out without needing
to specify any console= argument.