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Commit 087b6cb1 authored by Linus Torvalds's avatar Linus Torvalds Committed by Greg Kroah-Hartman
Browse files

vgacon: remove software scrollback support 



commit 973c096f6a85e5b5f2a295126ba6928d9a6afd45 upstream.

Yunhai Zhang recently fixed a VGA software scrollback bug in commit
ebfdfeeae8c0 ("vgacon: Fix for missing check in scrollback handling"),
but that then made people look more closely at some of this code, and
there were more problems on the vgacon side, but also the fbcon software
scrollback.

We don't really have anybody who maintains this code - probably because
nobody actually _uses_ it any more.  Sure, people still use both VGA and
the framebuffer consoles, but they are no longer the main user
interfaces to the kernel, and haven't been for decades, so these kinds
of extra features end up bitrotting and not really being used.

So rather than try to maintain a likely unused set of code, I'll just
aggressively remove it, and see if anybody even notices.  Maybe there
are people who haven't jumped on the whole GUI badnwagon yet, and think
it's just a fad.  And maybe those people use the scrollback code.

If that turns out to be the case, we can resurrect this again, once
we've found the sucker^Wmaintainer for it who actually uses it.

Reported-by: default avatarNopNop Nop <nopitydays@gmail.com>
Tested-by: default avatarWilly Tarreau <w@1wt.eu>
Cc: 张云海 <zhangyunhai@nsfocus.com>
Acked-by: default avatarAndy Lutomirski <luto@amacapital.net>
Acked-by: default avatarWilly Tarreau <w@1wt.eu>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0d123a8c

arch/powerpc/configs/pasemi_defconfig

+0 −1
Original line number Diff line number Diff line
@@ -109,7 +109,6 @@ CONFIG_FB_NVIDIA=y 
CONFIG_FB_NVIDIA_I2C=y

CONFIG_FB_RADEON=y

# CONFIG_LCD_CLASS_DEVICE is not set

CONFIG_VGACON_SOFT_SCROLLBACK=y

CONFIG_LOGO=y

CONFIG_SOUND=y

CONFIG_SND=y

arch/powerpc/configs/ppc6xx_defconfig

+0 −1
Original line number Diff line number Diff line
@@ -777,7 +777,6 @@ CONFIG_FB_TRIDENT=m 
CONFIG_FB_SM501=m

CONFIG_FB_IBM_GXT4500=y

CONFIG_LCD_PLATFORM=m

CONFIG_VGACON_SOFT_SCROLLBACK=y

CONFIG_FRAMEBUFFER_CONSOLE=y

CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y

CONFIG_LOGO=y

arch/x86/configs/i386_defconfig

+0 −1
Original line number Diff line number Diff line
@@ -204,7 +204,6 @@ CONFIG_FB_MODE_HELPERS=y 
CONFIG_FB_TILEBLITTING=y

CONFIG_FB_EFI=y

# CONFIG_LCD_CLASS_DEVICE is not set

CONFIG_VGACON_SOFT_SCROLLBACK=y

CONFIG_LOGO=y

# CONFIG_LOGO_LINUX_MONO is not set

# CONFIG_LOGO_LINUX_VGA16 is not set

arch/x86/configs/x86_64_defconfig

+0 −1
Original line number Diff line number Diff line
@@ -200,7 +200,6 @@ CONFIG_FB_MODE_HELPERS=y 
CONFIG_FB_TILEBLITTING=y

CONFIG_FB_EFI=y

# CONFIG_LCD_CLASS_DEVICE is not set

CONFIG_VGACON_SOFT_SCROLLBACK=y

CONFIG_LOGO=y

# CONFIG_LOGO_LINUX_MONO is not set

# CONFIG_LOGO_LINUX_VGA16 is not set

drivers/video/console/Kconfig

+0 −46
Original line number Diff line number Diff line
@@ -22,52 +22,6 @@ config VGA_CONSOLE 


	  Say Y.



config VGACON_SOFT_SCROLLBACK

       bool "Enable Scrollback Buffer in System RAM"

       depends on VGA_CONSOLE

       default n

       help

         The scrollback buffer of the standard VGA console is located in

	 the VGA RAM.  The size of this RAM is fixed and is quite small.

	 If you require a larger scrollback buffer, this can be placed in

	 System RAM which is dynamically allocated during initialization.

	 Placing the scrollback buffer in System RAM will slightly slow

	 down the console.



	 If you want this feature, say 'Y' here and enter the amount of

	 RAM to allocate for this buffer.  If unsure, say 'N'.



config VGACON_SOFT_SCROLLBACK_SIZE

       int "Scrollback Buffer Size (in KB)"

       depends on VGACON_SOFT_SCROLLBACK

       range 1 1024

       default "64"

       help

	  Enter the amount of System RAM to allocate for scrollback

	  buffers of VGA consoles. Each 64KB will give you approximately

	  16 80x25 screenfuls of scrollback buffer.



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 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)

	  will be broken, which might cause security issues.

	  You can use the escape sequence \e[3J instead if this feature is

	  activated.



	  Note that a buffer of VGACON_SOFT_SCROLLBACK_SIZE is taken for each

	  created tty device.

	  So if you use a RAM-constrained system, say N here.



config MDA_CONSOLE

	depends on !M68K && !PARISC && ISA

	tristate "MDA text console (dual-headed)"