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Message-ID: <20081025195814.GD10932@joi>
Date: Sat, 25 Oct 2008 21:58:19 +0200
From: Marcin Slusarz <marcin.slusarz@...il.com>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Antonino Daplas <adaplas@...il.com>,
Krzysztof Helt <krzysztof.h1@...pl>,
linux-fbdev-devel@...ts.sourceforge.net,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH RESEND] vgacon: remember scrollback buffer on console switch
Add 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: Krzysztof Helt <krzysztof.h1@...pl>
Cc: Andrew Morton <akpm@...ux-foundation.org>
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 2f50a80..09e3d98 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 MDA_CONSOLE
depends on !M68K && !PARISC && ISA
tristate "MDA text console (dual-headed) (EXPERIMENTAL)"
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 448d209..15ee7e1 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)
@@ -317,6 +380,10 @@ 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)
@@ -823,7 +890,7 @@ 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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