console: Add persistent scrollback buffers for all VGA consoles
Add a scrollback buffers for each VGA console. The benefit is that the scrollback history is not flushed when switching between consoles but is persistent. The buffers are allocated on demand when a new console is opened. This breaks tools like clear_console that rely on flushing the scrollback history by switching back and forth between consoles which is why this feature is disabled by default. Use the escape sequence \e[3J instead for flushing the buffer. Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de> Reviewed-by: Andrey Utkin <andrey_utkin@fastmail.com> Tested-by: Andrey Utkin <andrey_utkin@fastmail.com> Tested-by: Adam Borowski <kilobyte@angband.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Manuel Schölling
Greg Kroah-Hartman
Родитель
bcd375f7f7
Коммит
aabd31c421
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@ -43,9 +43,28 @@ config VGACON_SOFT_SCROLLBACK_SIZE
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range 1 1024
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default "64"
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help
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Enter the amount of System RAM to allocate for the scrollback
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buffer. Each 64KB will give you approximately 16 80x25
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screenfuls of scrollback buffer
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Enter the amount of System RAM to allocate for scrollback
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buffers of VGA consoles. Each 64KB will give you approximately
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16 80x25 screenfuls of scrollback buffer.
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config VGACON_SOFT_SCROLLBACK_PERSISTENT
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bool "Persistent Scrollback History for each console"
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depends on VGACON_SOFT_SCROLLBACK
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default n
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help
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Say Y here if the scrollback history should persist when switching
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between consoles. Otherwise, the scrollback history will be flushed
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each time the console is switched.
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This feature might break your tool of choice to flush the scrollback
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buffer, e.g. clear(1) will work fine but Debian's clear_console(1)
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will be broken, which might cause security issues.
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You can use the escape sequence \e[3J instead if this feature is
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activated.
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Note that a buffer of VGACON_SOFT_SCROLLBACK_SIZE is taken for each
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created tty device.
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So if you use a RAM-constrained system, say N here.
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config MDA_CONSOLE
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depends on !M68K && !PARISC && ISA
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@ -162,7 +162,7 @@ static inline void vga_set_mem_top(struct vc_data *c)
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#ifdef CONFIG_VGACON_SOFT_SCROLLBACK
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/* software scrollback */
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static struct vgacon_scrollback_info {
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struct vgacon_scrollback_info {
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void *data;
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int tail;
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int size;
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@ -171,74 +171,110 @@ static struct vgacon_scrollback_info {
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int cur;
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int save;
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int restore;
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} vgacon_scrollback;
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};
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static void vgacon_scrollback_reset(size_t reset_size)
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static struct vgacon_scrollback_info *vgacon_scrollback_cur;
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#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT
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static struct vgacon_scrollback_info vgacon_scrollbacks[MAX_NR_CONSOLES];
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#else
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static struct vgacon_scrollback_info vgacon_scrollbacks[1];
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#endif
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static void vgacon_scrollback_reset(int vc_num, size_t reset_size)
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{
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if (vgacon_scrollback.data && reset_size > 0)
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memset(vgacon_scrollback.data, 0, reset_size);
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struct vgacon_scrollback_info *scrollback = &vgacon_scrollbacks[vc_num];
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vgacon_scrollback.cnt = 0;
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vgacon_scrollback.tail = 0;
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vgacon_scrollback.cur = 0;
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if (scrollback->data && reset_size > 0)
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memset(scrollback->data, 0, reset_size);
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scrollback->cnt = 0;
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scrollback->tail = 0;
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scrollback->cur = 0;
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}
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static void vgacon_scrollback_init(int pitch)
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static void vgacon_scrollback_init(int vc_num)
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{
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int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
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int pitch = vga_video_num_columns * 2;
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size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024;
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int rows = size / pitch;
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void *data;
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if (vgacon_scrollback.data) {
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vgacon_scrollback.cnt = 0;
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vgacon_scrollback.tail = 0;
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vgacon_scrollback.cur = 0;
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vgacon_scrollback.rows = rows - 1;
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vgacon_scrollback.size = rows * pitch;
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data = kmalloc_array(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, 1024,
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GFP_NOWAIT);
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vgacon_scrollbacks[vc_num].data = data;
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vgacon_scrollback_cur = &vgacon_scrollbacks[vc_num];
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vgacon_scrollback_cur->rows = rows - 1;
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vgacon_scrollback_cur->size = rows * pitch;
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vgacon_scrollback_reset(vc_num, size);
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}
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static void vgacon_scrollback_switch(int vc_num)
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{
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#ifndef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT
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vc_num = 0;
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#endif
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if (!vgacon_scrollbacks[vc_num].data) {
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vgacon_scrollback_init(vc_num);
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} else {
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#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT
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vgacon_scrollback_cur = &vgacon_scrollbacks[vc_num];
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#else
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size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024;
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vgacon_scrollback_reset(vc_num, size);
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#endif
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}
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}
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static void vgacon_scrollback_startup(void)
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{
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vgacon_scrollback.data = kcalloc(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE,
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1024, GFP_NOWAIT);
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vgacon_scrollback_init(vga_video_num_columns * 2);
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vgacon_scrollback_cur = &vgacon_scrollbacks[0];
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vgacon_scrollback_init(0);
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}
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static void vgacon_scrollback_update(struct vc_data *c, int t, int count)
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{
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void *p;
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if (!vgacon_scrollback.size || c->vc_num != fg_console)
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if (!vgacon_scrollback_cur->data || !vgacon_scrollback_cur->size ||
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c->vc_num != fg_console)
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return;
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p = (void *) (c->vc_origin + t * c->vc_size_row);
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while (count--) {
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scr_memcpyw(vgacon_scrollback.data + vgacon_scrollback.tail,
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scr_memcpyw(vgacon_scrollback_cur->data +
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vgacon_scrollback_cur->tail,
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p, c->vc_size_row);
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vgacon_scrollback.cnt++;
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vgacon_scrollback_cur->cnt++;
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p += c->vc_size_row;
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vgacon_scrollback.tail += c->vc_size_row;
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vgacon_scrollback_cur->tail += c->vc_size_row;
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if (vgacon_scrollback.tail >= vgacon_scrollback.size)
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vgacon_scrollback.tail = 0;
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if (vgacon_scrollback_cur->tail >= vgacon_scrollback_cur->size)
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vgacon_scrollback_cur->tail = 0;
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if (vgacon_scrollback.cnt > vgacon_scrollback.rows)
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vgacon_scrollback.cnt = vgacon_scrollback.rows;
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if (vgacon_scrollback_cur->cnt > vgacon_scrollback_cur->rows)
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vgacon_scrollback_cur->cnt = vgacon_scrollback_cur->rows;
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vgacon_scrollback.cur = vgacon_scrollback.cnt;
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vgacon_scrollback_cur->cur = vgacon_scrollback_cur->cnt;
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}
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}
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static void vgacon_restore_screen(struct vc_data *c)
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{
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vgacon_scrollback.save = 0;
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vgacon_scrollback_cur->save = 0;
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if (!vga_is_gfx && !vgacon_scrollback.restore) {
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if (!vga_is_gfx && !vgacon_scrollback_cur->restore) {
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scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf,
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c->vc_screenbuf_size > vga_vram_size ?
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vga_vram_size : c->vc_screenbuf_size);
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vgacon_scrollback.restore = 1;
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vgacon_scrollback.cur = vgacon_scrollback.cnt;
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vgacon_scrollback_cur->restore = 1;
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vgacon_scrollback_cur->cur = vgacon_scrollback_cur->cnt;
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}
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}
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@ -252,41 +288,41 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines)
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return;
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}
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if (!vgacon_scrollback.data)
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if (!vgacon_scrollback_cur->data)
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return;
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if (!vgacon_scrollback.save) {
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if (!vgacon_scrollback_cur->save) {
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vgacon_cursor(c, CM_ERASE);
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vgacon_save_screen(c);
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vgacon_scrollback.save = 1;
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vgacon_scrollback_cur->save = 1;
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}
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vgacon_scrollback.restore = 0;
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start = vgacon_scrollback.cur + lines;
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vgacon_scrollback_cur->restore = 0;
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start = vgacon_scrollback_cur->cur + lines;
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end = start + abs(lines);
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if (start < 0)
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start = 0;
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if (start > vgacon_scrollback.cnt)
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start = vgacon_scrollback.cnt;
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if (start > vgacon_scrollback_cur->cnt)
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start = vgacon_scrollback_cur->cnt;
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if (end < 0)
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end = 0;
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if (end > vgacon_scrollback.cnt)
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end = vgacon_scrollback.cnt;
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if (end > vgacon_scrollback_cur->cnt)
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end = vgacon_scrollback_cur->cnt;
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vgacon_scrollback.cur = start;
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vgacon_scrollback_cur->cur = start;
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count = end - start;
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soff = vgacon_scrollback.tail - ((vgacon_scrollback.cnt - end) *
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c->vc_size_row);
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soff = vgacon_scrollback_cur->tail -
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((vgacon_scrollback_cur->cnt - end) * c->vc_size_row);
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soff -= count * c->vc_size_row;
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if (soff < 0)
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soff += vgacon_scrollback.size;
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soff += vgacon_scrollback_cur->size;
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count = vgacon_scrollback.cnt - start;
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count = vgacon_scrollback_cur->cnt - start;
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if (count > c->vc_rows)
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count = c->vc_rows;
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@ -300,13 +336,13 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines)
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count *= c->vc_size_row;
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/* how much memory to end of buffer left? */
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copysize = min(count, vgacon_scrollback.size - soff);
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scr_memcpyw(d, vgacon_scrollback.data + soff, copysize);
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copysize = min(count, vgacon_scrollback_cur->size - soff);
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scr_memcpyw(d, vgacon_scrollback_cur->data + soff, copysize);
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d += copysize;
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count -= copysize;
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if (count) {
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scr_memcpyw(d, vgacon_scrollback.data, count);
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scr_memcpyw(d, vgacon_scrollback_cur->data, count);
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d += count;
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}
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@ -320,13 +356,13 @@ static void vgacon_flush_scrollback(struct vc_data *c)
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{
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size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024;
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if (c->vc_num == fg_console)
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vgacon_scrollback_reset(size);
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vgacon_scrollback_reset(c->vc_num, size);
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}
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#else
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#define vgacon_scrollback_startup(...) do { } while (0)
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#define vgacon_scrollback_init(...) do { } while (0)
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#define vgacon_scrollback_update(...) do { } while (0)
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#define vgacon_scrollback_switch(...) do { } while (0)
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static void vgacon_restore_screen(struct vc_data *c)
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{
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@ -805,7 +841,7 @@ static int vgacon_switch(struct vc_data *c)
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vgacon_doresize(c, c->vc_cols, c->vc_rows);
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}
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vgacon_scrollback_init(c->vc_size_row);
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vgacon_scrollback_switch(c->vc_num);
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return 0; /* Redrawing not needed */
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}
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