On Tue, 2017-01-10 at 23:58 +0100, Adam Borowski wrote:

On Tue, Jan 10, 2017 at 10:28:38PM +0100, Manuel Schölling wrote:

quoted

The impact of the persistent scrollback feature on the code size is
rather small, so the config option is removed. The feature stays
disabled by default and can be enabled by using the boot command
line
parameter 'vgacon.scrollback_persistent=1' or by setting
VGACON_SOFT_SCROLLBACK_PERSISTENT_ENABLE_BY_DEFAULT=y.

Signed-off-by: Manuel Schölling <redacted>
Suggested-by: Bartlomiej Zolnierkiewicz <redacted>
+module_param_named(scrollback_persistent, scrollback_persistent,
bool, 0000);
+MODULE_PARM_DESC(scrollback_persistent, "Enable persistent
scrollback for all vga consoles");

A command-line knob settable by the end-user is something more
persistent
than a config option.  As you're going to extend this code beyond
vgacon in
the near future, perhaps it'd be better to have a shared setting for
all
console drivers?

Probably a good idea, but I'm struggling with the implementation a bit:

I tried to run 

  if (strstr(boot_command_line, "nopersistentscrollback")) {...}

in vgacon_scrollback_startup() but I am getting 

  WARNING: modpost: Found 2 section mismatch(es).

when compiling. Probably because vgacon_scrollback_startup() is
executed after init.

I tried to find another way to implement a boot cmd line parameter but
had no luck.
If you/somebody could point me in the right direction, it would be very
much appreciated.

Thanks!

Manuel