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Ethan Nelson-Moore
e38b27199e
The mdacon driver supports using ISA MDA or Hercules-compatible display
adapters as a secondary text console. This was commonly used in the
1990s and earlier for debugging software which took over the primary
display. It is highly unlikely anyone is doing so nowadays because
serial consoles and much better methods of debugging exist.
The driver is not enabled by any defconfig, nor any of the
dozens of distro configs collected at [1]. It has been relegated to VTs
13-16 since commit 0b9cf3aa6b ("mdacon messing up default vc's - set
default to vc13-16 again") in Linux 2.6.27 (and before Linux 2.5.53 -
see the link in the message of the above commit). The change in 2.6.27
was done because it was incorrectly detecting non-MDA adapters as MDA
and taking over all VTs, rendering them unusable.
Furthermore, vgacon supports using MDA/Hercules-compatible adapters as
the primary text console, so any systems with only one of these
adapters were already using vgacon and will not experience any loss in
functionality from the removal of this driver.
Given all of these factors, the mdacon driver is likely entirely
unused. Remove it.
[1] https://github.com/nyrahul/linux-kernel-configs/tree/f0bee86a135a0406ea427855f52702dd00d770f9
Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
50 lines
1.1 KiB
C
50 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* include/linux/vt_buffer.h -- Access to VT screen buffer
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*
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* (c) 1998 Martin Mares <mj@ucw.cz>
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*
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* This is a set of macros and functions which are used in the
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* console driver and related code to access the screen buffer.
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* In most cases the console works with simple in-memory buffer,
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* but when handling hardware text mode consoles, we store
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* the foreground console directly in video memory.
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*/
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#ifndef _LINUX_VT_BUFFER_H_
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#define _LINUX_VT_BUFFER_H_
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#include <linux/string.h>
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#if IS_ENABLED(CONFIG_VGA_CONSOLE)
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#include <asm/vga.h>
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#endif
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#ifndef VT_BUF_HAVE_RW
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#define scr_writew(val, addr) (*(addr) = (val))
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#define scr_readw(addr) (*(addr))
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#endif
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#ifndef VT_BUF_HAVE_MEMSETW
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static inline void scr_memsetw(u16 *s, u16 c, unsigned int count)
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{
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memset16(s, c, count / 2);
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}
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#endif
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#ifndef VT_BUF_HAVE_MEMCPYW
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static inline void scr_memcpyw(u16 *d, const u16 *s, unsigned int count)
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{
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memcpy(d, s, count);
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}
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#endif
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#ifndef VT_BUF_HAVE_MEMMOVEW
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static inline void scr_memmovew(u16 *d, const u16 *s, unsigned int count)
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{
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memmove(d, s, count);
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}
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#endif
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#endif
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