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Commit 1a336c93 authored by Manuel Schölling's avatar Manuel Schölling Committed by Greg Kroah-Hartman
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console: Make persistent scrollback a boot parameter 



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: default avatarManuel Schölling <manuel.schoelling@gmx.de>
Suggested-by: default avatarBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent aabd31c4

drivers/video/console/Kconfig

+7 −5
Original line number Diff line number Diff line
@@ -47,14 +47,16 @@ config VGACON_SOFT_SCROLLBACK_SIZE 
	  buffers of VGA consoles. Each 64KB will give you approximately

	  16 80x25 screenfuls of scrollback buffer.



config VGACON_SOFT_SCROLLBACK_PERSISTENT

	bool "Persistent Scrollback History for each console"

config VGACON_SOFT_SCROLLBACK_PERSISTENT_ENABLE_BY_DEFAULT

	bool "Persistent Scrollback History for each console by default"

	depends on VGACON_SOFT_SCROLLBACK

	default n

	help

	  Say Y here if the scrollback history should persist when switching

	  between consoles. Otherwise, the scrollback history will be flushed

	  each time the console is switched.

	  Say Y here if the scrollback history should persist by default when

	  switching between consoles. Otherwise, the scrollback history will be

	  flushed each time the console is switched. This feature can also be

	  enabled using the boot command line parameter

	  'vgacon.scrollback_persistent=1'.



	  This feature might break your tool of choice to flush the scrollback

	  buffer, e.g. clear(1) will work fine but Debian's clear_console(1)

drivers/video/console/vgacon.c

+12 −13
Original line number Diff line number Diff line
@@ -174,11 +174,11 @@ struct vgacon_scrollback_info { 
};



static struct vgacon_scrollback_info *vgacon_scrollback_cur;

#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT

static struct vgacon_scrollback_info vgacon_scrollbacks[MAX_NR_CONSOLES];

#else

static struct vgacon_scrollback_info vgacon_scrollbacks[1];

#endif

static bool scrollback_persistent = \

	IS_ENABLED(CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT_ENABLE_BY_DEFAULT);

module_param_named(scrollback_persistent, scrollback_persistent, bool, 0000);

MODULE_PARM_DESC(scrollback_persistent, "Enable persistent scrollback for all vga consoles");



static void vgacon_scrollback_reset(int vc_num, size_t reset_size)

{
@@ -213,20 +213,19 @@ static void vgacon_scrollback_init(int vc_num) 


static void vgacon_scrollback_switch(int vc_num)

{

#ifndef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT

	if (!scrollback_persistent)

		vc_num = 0;

#endif



	if (!vgacon_scrollbacks[vc_num].data) {

		vgacon_scrollback_init(vc_num);

	} else {

#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT

		if (scrollback_persistent) {

			vgacon_scrollback_cur = &vgacon_scrollbacks[vc_num];

#else

		} else {

			size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024;



			vgacon_scrollback_reset(vc_num, size);

#endif

		}

	}

}