linux-hardened/include/linux/vt_buffer.h
Dave Airlie 67dc0d4758 vt_buffer: drop console buffer copying optimisations
These two copy to/from VGA memory, however on the Silicon
Motion SMI750 VGA card on a 64-bit system cause console corruption.

This is due to the hw being buggy and not handling a 64-bit transaction
correctly.

We could try and create a 32-bit version of these routines,
but I'm not sure the optimisation is worth much today.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1132826

Tested-by: Huawei engineering.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-02 10:09:54 -08:00

59 lines
1.3 KiB
C

/*
* include/linux/vt_buffer.h -- Access to VT screen buffer
*
* (c) 1998 Martin Mares <mj@ucw.cz>
*
* This is a set of macros and functions which are used in the
* console driver and related code to access the screen buffer.
* In most cases the console works with simple in-memory buffer,
* but when handling hardware text mode consoles, we store
* the foreground console directly in video memory.
*/
#ifndef _LINUX_VT_BUFFER_H_
#define _LINUX_VT_BUFFER_H_
#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE)
#include <asm/vga.h>
#endif
#ifndef VT_BUF_HAVE_RW
#define scr_writew(val, addr) (*(addr) = (val))
#define scr_readw(addr) (*(addr))
#endif
#ifndef VT_BUF_HAVE_MEMSETW
static inline void scr_memsetw(u16 *s, u16 c, unsigned int count)
{
count /= 2;
while (count--)
scr_writew(c, s++);
}
#endif
#ifndef VT_BUF_HAVE_MEMCPYW
static inline void scr_memcpyw(u16 *d, const u16 *s, unsigned int count)
{
count /= 2;
while (count--)
scr_writew(scr_readw(s++), d++);
}
#endif
#ifndef VT_BUF_HAVE_MEMMOVEW
static inline void scr_memmovew(u16 *d, const u16 *s, unsigned int count)
{
if (d < s)
scr_memcpyw(d, s, count);
else {
count /= 2;
d += count;
s += count;
while (count--)
scr_writew(scr_readw(--s), --d);
}
}
#endif
#endif