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Date: Sun, 21 Sep 2008 18:02:18 +0200
From: Marcin Slusarz <marcin.slusarz@...il.com>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Antonino Daplas <adaplas@...il.com>,
linux-fbdev-devel@...ts.sourceforge.net
Subject: [PATCH] vgacon: remember scrollback buffer on console switch
This patch adds support for persistent console history, surviving
console switches. It allocates new scrollback buffer only when
user switches console for the first time.
Signed-off-by: Marcin Slusarz <marcin.slusarz@...il.com>
Cc: Antonino Daplas <adaplas@...il.com>
Cc: linux-fbdev-devel@...ts.sourceforge.net
---
drivers/video/console/Kconfig | 11 ++++++
drivers/video/console/vgacon.c | 75 +++++++++++++++++++++++++++++++++++++--
2 files changed, 82 insertions(+), 4 deletions(-)
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 06f87b0..9efb885 100644
--- a/drivers/video/console/Kconfig
+++ b/drivers/video/console/Kconfig
@@ -43,6 +43,17 @@ config VGACON_SOFT_SCROLLBACK_SIZE
buffer. Each 64KB will give you approximately 16 80x25
screenfuls of scrollback buffer
+config VGACON_REMEMBER_SCROLLBACK
+ bool "Remember scrollback buffer on console switch"
+ depends on VGACON_SOFT_SCROLLBACK
+ default y
+ help
+ Say 'Y' here if you want the scrollback buffer to be remembered
+ on console switch and restored when you switch back.
+
+ Note: every VGA console will use its own buffer, but it will be
+ allocated only when you switch to this console for the first time.
+
config VIDEO_SELECT
bool "Video mode selection support"
depends on X86 && VGA_CONSOLE
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index a785f99..94ce971 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -174,9 +174,11 @@ static int vgacon_scrollback_cur;
static int vgacon_scrollback_save;
static int vgacon_scrollback_restore;
+#define SCROLLBACK_SIZE (CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024)
+
static void vgacon_scrollback_init(int pitch)
{
- int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
+ int rows = SCROLLBACK_SIZE / pitch;
if (vgacon_scrollback) {
vgacon_scrollback_cnt = 0;
@@ -187,15 +189,76 @@ static void vgacon_scrollback_init(int pitch)
}
}
+#ifdef CONFIG_VGACON_REMEMBER_SCROLLBACK
+static struct vgacon_scrollback_info {
+ void *data;
+ int cnt;
+ int tail;
+ int cur;
+ int rows;
+ int size;
+} vgacon_scrollbacks[MAX_NR_CONSOLES];
+static int vgacon_last_vc_num;
+
+static void vgacon_switch_scrollback(struct vc_data *c)
+{
+ int num = c->vc_num;
+ struct vgacon_scrollback_info *old_scrollback =
+ &vgacon_scrollbacks[vgacon_last_vc_num];
+ struct vgacon_scrollback_info *new_scrollback =
+ &vgacon_scrollbacks[num];
+
+ old_scrollback->cnt = vgacon_scrollback_cnt;
+ old_scrollback->tail = vgacon_scrollback_tail;
+ old_scrollback->cur = vgacon_scrollback_cur;
+ old_scrollback->rows = vgacon_scrollback_rows;
+ old_scrollback->size = vgacon_scrollback_size;
+
+ if (!new_scrollback->data) {
+ int rows = SCROLLBACK_SIZE / c->vc_size_row;
+
+ new_scrollback->data = kmalloc(SCROLLBACK_SIZE, GFP_KERNEL);
+ new_scrollback->cnt = 0;
+ new_scrollback->tail = 0;
+ new_scrollback->cur = 0;
+ new_scrollback->rows = rows - 1;
+ new_scrollback->size = rows * c->vc_size_row;
+
+ if (!new_scrollback->data) {
+ printk(KERN_WARNING "VGAcon: failed to allocate memory for scrollback of console %d, using scrollback of console %d.\n",
+ num, vgacon_last_vc_num);
+ new_scrollback->data = old_scrollback->data;
+ old_scrollback->data = NULL;
+ }
+ }
+
+ vgacon_scrollback = new_scrollback->data;
+ vgacon_scrollback_cnt = new_scrollback->cnt;
+ vgacon_scrollback_tail = new_scrollback->tail;
+ vgacon_scrollback_cur = new_scrollback->cur;
+ vgacon_scrollback_rows = new_scrollback->rows;
+ vgacon_scrollback_size = new_scrollback->size;
+
+ vgacon_last_vc_num = num;
+}
+#else
+static inline void vgacon_switch_scrollback(struct vc_data *c)
+{
+ vgacon_scrollback_init(c->vc_size_row);
+}
+#endif
/*
* Called only duing init so call of alloc_bootmen is ok.
* Marked __init_refok to silence modpost.
*/
static void __init_refok vgacon_scrollback_startup(void)
{
- vgacon_scrollback = alloc_bootmem(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE
- * 1024);
+ vgacon_scrollback = alloc_bootmem(SCROLLBACK_SIZE);
vgacon_scrollback_init(vga_video_num_columns * 2);
+#ifdef CONFIG_VGACON_REMEMBER_SCROLLBACK
+ vgacon_scrollbacks[0].data = vgacon_scrollback;
+ vgacon_last_vc_num = 0;
+#endif
}
static void vgacon_scrollback_update(struct vc_data *c, int t, int count)
@@ -318,6 +381,10 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
#define vgacon_scrollback_init(...) do { } while (0)
#define vgacon_scrollback_update(...) do { } while (0)
+static inline void vgacon_switch_scrollback(struct vc_data *c)
+{
+}
+
static void vgacon_restore_screen(struct vc_data *c)
{
if (c->vc_origin != c->vc_visible_origin)
@@ -824,7 +891,7 @@ static int vgacon_switch(struct vc_data *c)
vgacon_doresize(c, c->vc_cols, c->vc_rows);
}
- vgacon_scrollback_init(c->vc_size_row);
+ vgacon_switch_scrollback(c);
return 0; /* Redrawing not needed */
}
--
1.5.6.4
--
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