@@ -656,7 +656,7 @@ static inline void save_screen(struct vc_data *vc)
* Redrawing of screen
*/
-static void clear_buffer_attributes(struct vc_data *vc)
+void clear_buffer_attributes(struct vc_data *vc)
{
unsigned short *p = (unsigned short *)vc->vc_origin;
int count = vc->vc_screenbuf_size / 2;
@@ -1064,7 +1064,7 @@ static int vgacon_do_font_op(struct vgastate *state,char *arg,int set,int ch512)
unsigned short video_port_status = vga_video_port_reg + 6;
int font_select = 0x00, beg, i;
char *charmap;
-
+ bool clear_attribs = false;
if (vga_video_type != VIDEO_TYPE_EGAM) {
charmap = (char *) VGA_MAP_MEM(colourmap, 0);
beg = 0x0e;
@@ -1169,12 +1169,6 @@ static int vgacon_do_font_op(struct vgastate *state,char *arg,int set,int ch512)
/* if 512 char mode is already enabled don't re-enable it. */
if ((set) && (ch512 != vga_512_chars)) {
- /* attribute controller */
- for (i = 0; i < MAX_NR_CONSOLES; i++) {
- struct vc_data *c = vc_cons[i].d;
- if (c && c->vc_sw == &vga_con)
- c->vc_hi_font_mask = ch512 ? 0x0800 : 0;
- }
vga_512_chars = ch512;
/* 256-char: enable intensity bit
512-char: disable intensity bit */
@@ -1185,8 +1179,22 @@ static int vgacon_do_font_op(struct vgastate *state,char *arg,int set,int ch512)
it means, but it works, and it appears necessary */
inb_p(video_port_status);
vga_wattr(state->vgabase, VGA_AR_ENABLE_DISPLAY, 0);
+ clear_attribs = true;
}
raw_spin_unlock_irq(&vga_lock);
+
+ if (clear_attribs) {
+ for (i = 0; i < MAX_NR_CONSOLES; i++) {
+ struct vc_data *c = vc_cons[i].d;
+ if (c && c->vc_sw == &vga_con) {
+ /* force hi font mask to 0, so we always clear
+ the bit on either transition */
+ c->vc_hi_font_mask = 0x00;
+ clear_buffer_attributes(c);
+ c->vc_hi_font_mask = ch512 ? 0x0800 : 0;
+ }
+ }
+ }
return 0;
}
@@ -47,6 +47,7 @@ int con_set_cmap(unsigned char __user *cmap);
int con_get_cmap(unsigned char __user *cmap);
void scrollback(struct vc_data *vc, int lines);
void scrollfront(struct vc_data *vc, int lines);
+void clear_buffer_attributes(struct vc_data *vc);
void update_region(struct vc_data *vc, unsigned long start, int count);
void redraw_screen(struct vc_data *vc, int is_switch);
#define update_screen(x) redraw_screen(x, 0)
This is a note to let you know that I have just added a patch titled vgacon/vt: clear buffer attributes when we load a 512 to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From c37b5217bd53d6f3d596232703486ed3d5d21788 Mon Sep 17 00:00:00 2001 From: Dave Airlie <airlied@redhat.com> Date: Thu, 24 Jan 2013 14:14:19 +1000 Subject: [PATCH] vgacon/vt: clear buffer attributes when we load a 512 character font (v2) commit 2a2483072393b27f4336ab068a1f48ca19ff1c1e upstream. When we switch from 256->512 byte font rendering mode, it means the current contents of the screen is being reinterpreted. The bit that holds the high bit of the 9-bit font, may have been previously set, and thus the new font misrenders. The problem case we see is grub2 writes spaces with the bit set, so it ends up with data like 0x820, which gets reinterpreted into 0x120 char which the font translates into G with a circumflex. This flashes up on screen at boot and is quite ugly. A current side effect of this patch though is that any rendering on the screen changes color to a slightly darker color, but at least the screen no longer corrupts. v2: as suggested by hpa, always clear the attribute space, whether we are are going to or from 512 chars. Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/tty/vt/vt.c | 2 +- drivers/video/console/vgacon.c | 22 +++++++++++++++------- include/linux/vt_kern.h | 1 + 3 files changed, 17 insertions(+), 8 deletions(-) -- 1.8.1.2