UBUNTU: SAUCE: vt -- maintain bootloader screen mode and content until vt switch

Introduce a new VT mode KD_TRANSPARENT which endevours to leave the current
content of the framebuffer untouched.  This allows the bootloader to insert
a graphical splash and have the kernel maintain it until the OS splash
can take over.  When we finally switch away (either through programs like
plymouth or manually) the content is lost and the VT reverts to text mode.

BugLink: http://bugs.launchpad.net/bugs/1308685
Signed-off-by: Andy Whitcroft <apw@canonical.com>

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 34aa39d1aed9f4d8a3f5f4e31bf615b67cc6b505..bc696d30dd3a8339e7ca23abb72dfab3e7179b49 100644 (file)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -105,6 +105,7 @@
 #include <linux/ctype.h>
 #include <linux/bsearch.h>
 #include <linux/gcd.h>
+#include <linux/screen_info.h>
 
 #define MAX_NR_CON_DRIVER 16
 
@@ -149,7 +150,7 @@ static const struct consw *con_driver_map[MAX_NR_CONSOLES];
 
 static int con_open(struct tty_struct *, struct file *);
 static void vc_init(struct vc_data *vc, unsigned int rows,
-                   unsigned int cols, int do_clear);
+                   unsigned int cols, int do_clear, int mode);
 static void gotoxy(struct vc_data *vc, int new_x, int new_y);
 static void save_cur(struct vc_data *vc);
 static void reset_terminal(struct vc_data *vc, int do_clear);
@@ -173,6 +174,9 @@ module_param(global_cursor_default, int, S_IRUGO | S_IWUSR);
 static int cur_default = CUR_DEFAULT;
 module_param(cur_default, int, S_IRUGO | S_IWUSR);
 
+int vt_handoff = 0;
+module_param_named(handoff, vt_handoff, int, S_IRUGO | S_IWUSR);
+
 /*
  * ignore_poke: don't unblank the screen when things are typed.  This is
  * mainly for the privacy of braille terminal users.
@@ -984,6 +988,13 @@ void redraw_screen(struct vc_data *vc, int is_switch)
                }
                if (tty0dev)
                        sysfs_notify(&tty0dev->kobj, NULL, "active");
+               /*
+                * If we are switching away from a transparent VT the contents
+                * will be lost, convert it into a blank text console then
+                * it will be repainted blank if we ever switch back.
+                */
+               if (old_vc->vc_mode == KD_TRANSPARENT)
+                       old_vc->vc_mode = KD_TEXT;
        } else {
                hide_cursor(vc);
                redraw = 1;
@@ -1104,7 +1115,7 @@ int vc_allocate(unsigned int currcons)    /* return 0 on success */
        if (global_cursor_default == -1)
                global_cursor_default = 1;
 
-       vc_init(vc, vc->vc_rows, vc->vc_cols, 1);
+       vc_init(vc, vc->vc_rows, vc->vc_cols, 1, KD_TEXT);
        vcs_make_sysfs(currcons);
        atomic_notifier_call_chain(&vt_notifier_list, VT_ALLOCATE, &param);
 
@@ -3287,7 +3298,7 @@ module_param_named(italic, default_italic_color, int, S_IRUGO | S_IWUSR);
 module_param_named(underline, default_underline_color, int, S_IRUGO | S_IWUSR);
 
 static void vc_init(struct vc_data *vc, unsigned int rows,
-                   unsigned int cols, int do_clear)
+                   unsigned int cols, int do_clear, int mode)
 {
        int j, k ;
 
@@ -3298,7 +3309,7 @@ static void vc_init(struct vc_data *vc, unsigned int rows,
 
        set_origin(vc);
        vc->vc_pos = vc->vc_origin;
-       reset_vc(vc);
+       reset_vc(vc, mode);
        for (j=k=0; j<16; j++) {
                vc->vc_palette[k++] = default_red[j] ;
                vc->vc_palette[k++] = default_grn[j] ;
@@ -3355,16 +3366,32 @@ static int __init con_init(void)
                mod_timer(&console_timer, jiffies + (blankinterval * HZ));
        }
 
+       if (vt_handoff > 0 && vt_handoff <= MAX_NR_CONSOLES) {
+               currcons = vt_handoff - 1;
+               vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT);
+               INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
+               tty_port_init(&vc->port);
+               visual_init(vc, currcons, 1);
+               vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT);
+               vc_init(vc, vc->vc_rows, vc->vc_cols, 0, KD_TRANSPARENT);
+       }
        for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) {
+               if (currcons == vt_handoff - 1)
+                       continue;
                vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT);
                INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
                tty_port_init(&vc->port);
                visual_init(vc, currcons, 1);
                vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT);
                vc_init(vc, vc->vc_rows, vc->vc_cols,
-                       currcons || !vc->vc_sw->con_save_screen);
+                       currcons || !vc->vc_sw->con_save_screen, KD_TEXT);
        }
        currcons = fg_console = 0;
+       if (vt_handoff > 0) {
+               printk(KERN_INFO "vt handoff: transparent VT on vt#%d\n",
+                                                               vt_handoff);
+               currcons = fg_console = vt_handoff - 1;
+       }
        master_display_fg = vc = vc_cons[currcons].d;
        set_origin(vc);
        save_screen(vc);

diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index 8b0ed139592f95bf4c42fdfbd88273dec874372e..f19735eb52651c7864de9acbdad419e54c1e82a5 100644 (file)
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -1027,9 +1027,9 @@ out:
        return ret;
 }
 
-void reset_vc(struct vc_data *vc)
+void reset_vc(struct vc_data *vc, int mode)
 {
-       vc->vc_mode = KD_TEXT;
+       vc->vc_mode = mode;
        vt_reset_unicode(vc->vc_num);
        vc->vt_mode.mode = VT_AUTO;
        vc->vt_mode.waitv = 0;
@@ -1061,7 +1061,7 @@ void vc_SAK(struct work_struct *work)
                 */
                if (tty)
                        __do_SAK(tty);
-               reset_vc(vc);
+               reset_vc(vc, KD_TEXT);
        }
        console_unlock();
 }
@@ -1301,7 +1301,7 @@ static void complete_change_console(struct vc_data *vc)
                 * this outside of VT_PROCESS but there is no single process
                 * to account for and tracking tty count may be undesirable.
                 */
-                       reset_vc(vc);
+                       reset_vc(vc, KD_TEXT);
 
                        if (old_vc_mode != vc->vc_mode) {
                                if (vc->vc_mode == KD_TEXT)
@@ -1373,7 +1373,7 @@ void change_console(struct vc_data *new_vc)
                 * this outside of VT_PROCESS but there is no single process
                 * to account for and tracking tty count may be undesirable.
                 */
-               reset_vc(vc);
+               reset_vc(vc, KD_TEXT);
 
                /*
                 * Fall through to normal (VT_AUTO) handling of the switch...

diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h
index 8dc77e40bc03875a3adfde0d85a8441a627ab4f0..649675431071db1fb28bd9bc33c29a736a93c69b 100644 (file)
--- a/include/linux/vt_kern.h
+++ b/include/linux/vt_kern.h
@@ -130,7 +130,8 @@ int con_copy_unimap(struct vc_data *dst_vc, struct vc_data *src_vc)
 void vt_event_post(unsigned int event, unsigned int old, unsigned int new);
 int vt_waitactive(int n);
 void change_console(struct vc_data *new_vc);
-void reset_vc(struct vc_data *vc);
+void reset_vc(struct vc_data *vc, int mode);
+
 extern int do_unbind_con_driver(const struct consw *csw, int first, int last,
                             int deflt);
 int vty_init(const struct file_operations *console_fops);

diff --git a/include/uapi/linux/kd.h b/include/uapi/linux/kd.h
index 4616b31f84da295fd5147b432d035f05a2a06a7c..a05a246c4d293d9eaa447154c2940c54088bfa9f 100644 (file)
--- a/include/uapi/linux/kd.h
+++ b/include/uapi/linux/kd.h
@@ -46,6 +46,8 @@ struct consolefontdesc {
 #define                KD_GRAPHICS     0x01
 #define                KD_TEXT0        0x02    /* obsolete */
 #define                KD_TEXT1        0x03    /* obsolete */
+#define                KD_TRANSPARENT  0x04
+
 #define KDGETMODE      0x4B3B  /* get current mode */
 
 #define KDMAPDISP      0x4B3C  /* map display into address space */