Use of /sys/class/tty/console/active breaks OLPC splash

[Daniel Drake]

Hi,

Due to recent fixes in git and also packaged in Fedora, plymouth is
now reading from /sys/class/tty/console/active instead of using the
kernel command line.
This has broken splash for OLPC.

On OLPC, this file has contents: ttyS0 tty0
As described in the kernel documentation, the final one is the primary
tty, in our case tty0.

I can't get my head around plymouth's logic here.

If I'm reading add_consoles_from_file() correctly, if
/sys/class/tty/console/active has any contents at all, the graphical
splash will be disabled due to the following line:
      state->should_force_details = true;

Also, there is a bug in the loop here:

      console_length = strlen (console);
      ...
      remaining_command_line += console_length;


As strlen doesn't include the null-byte, remaining_command_line is not
fast-forwarded enough, meaning that the "tty0" console above is never
read.

If I remove the should_force_details=true line, and increment
remaining_command_line by one, both displays get added as follows:

[main.c]                        initialize_environment:initializing
minimal work environment
[main.c]                               check_verbosity:checking if
tracing should be enabled
[main.c]                               check_verbosity:tracing
shouldn't be enabled!
[main.c]                                 check_logging:checking if
console messages should be redirected and logged
[main.c]                                 check_logging:logging will be enabled!
[main.c]                        initialize_environment:source built on
Apr  9 2012
[main.c]                        initialize_environment:checking if
'/dev/tty1' exists
[main.c]                            check_for_consoles:checking for consoles
[main.c]                        add_consoles_from_file:opening
/sys/class/tty/console/active
[main.c]                        add_consoles_from_file:reading file
[main.c]                        add_consoles_from_file:console /dev/ttyS0 found!
[main.c]                        add_consoles_from_file:console /dev/tty0 found!
[main.c]                            check_for_consoles:After
processing serial consoles there are now 0 text displays
[main.c]                        initialize_environment:Making sure
/var/run/plymouth exists
[ply-utils.c]                          ply_create_directory:directory
'/var/run/plymouth' already exists
[main.c]                        initialize_environment:initialized
minimal work environment
[main.c]                       get_cache_file_for_mode:returning cache
file '/var/lib/plymouth//boot-duration'
[main.c]                                          main:entering event loop
[ply-boot-server.c]
print_connection_process_identity:connection is from pid 3157
(plymouth show-splash) with parent pid 1091 (-bash)
[ply-boot-server.c]                ply_boot_connection_on_request:got
show splash request
[main.c]      plymouth_should_ignore_show_splash_calls:checking if
plymouth should be running
[main.c]                            check_for_consoles:checking for
consoles and adding displays
[main.c]                        add_consoles_from_file:opening
/sys/class/tty/console/active
[main.c]                        add_consoles_from_file:reading file
[main.c]                        add_consoles_from_file:console /dev/ttyS0 found!
[main.c]                        add_consoles_from_file:console /dev/tty0 found!
[main.c]          add_display_and_keyboard_for_console:adding display
and keyboard for console /dev/ttyS0
[main.c]                                  set_keyboard:listening for keystrokes
[main.c]                                  set_keyboard:listening for backspace
[main.c]                                  set_keyboard:listening for enter
[main.c]          add_display_and_keyboard_for_console:adding display
and keyboard for console /dev/tty1
[main.c]                                  set_keyboard:listening for keystrokes
[main.c]                                  set_keyboard:listening for backspace
[main.c]                                  set_keyboard:listening for enter
[main.c]                            check_for_consoles:After
processing serial consoles there are now 2 text displays


However things are still not right - no graphical splash appears.
The fact that 2 text displays have been registered means that when we get here:

  if (should_add_displays && ply_list_get_length (state->text_displays) == 0)
    add_default_displays_and_keyboard (state);

since we have 2  text_displays we dont bother calling
add_default_displays_and_keyboard, which means that we never add any
pixel displays --> no splash.
Bit lost in the logic here; how is this supposed to work?

Thanks
Daniel