2006-05-02 22:57:54

by Jordan Crouse

[permalink] [raw]

Subject: [PATCH] vt: Delay the update of the visible framebuffer console

---

[PATCH] vt: Delay the update of the visible framebuffer console

From: David Hollister <[email protected]>

This patch delays the update of the visible framebuffer console until
all other consoles have been initialized in order to avoid losing
information. This only seems to be a problem with modules, not with
built-in drivers.

Signed-off-by: David Hollister <[email protected]>
Signed-off-by: Jordan Crouse <[email protected]>
---

drivers/char/vt.c | 22 ++++++++++++++--------
1 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index acc5d47..30f0f24 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -2700,9 +2700,11 @@ int take_over_console(const struct consw
if (!vc || !vc->vc_sw)
continue;

- j = i;
- if (CON_IS_VISIBLE(vc))
+ if (CON_IS_VISIBLE(vc)) {
+ j = i;
save_screen(vc);
+ }
+
old_was_color = vc->vc_can_do_color;
vc->vc_sw->con_deinit(vc);
vc->vc_origin = (unsigned long)vc->vc_screenbuf;
@@ -2718,17 +2720,21 @@ int take_over_console(const struct consw
*/
if (old_was_color != vc->vc_can_do_color)
clear_buffer_attributes(vc);
-
- if (CON_IS_VISIBLE(vc))
- update_screen(vc);
}
+
printk("Console: switching ");
if (!deflt)
printk("consoles %d-%d ", first+1, last+1);
- if (j >= 0)
+ if (j >= 0) {
+ struct vc_data *vc = vc_cons[j].d;
+
printk("to %s %s %dx%d\n",
- vc_cons[j].d->vc_can_do_color ? "colour" : "mono",
- desc, vc_cons[j].d->vc_cols, vc_cons[j].d->vc_rows);
+ vc->vc_can_do_color ? "colour" : "mono",
+ desc, vc->vc_cols, vc->vc_rows);
+
+ if (CON_IS_VISIBLE(vc))
+ update_screen(vc);
+ }
else
printk("to %s\n", desc);

---

Attachments:

(No filename) (258.00 B)
vt.patch (1.69 kB)
Download all attachments

2006-05-02 23:22:40

by Antonino A. Daplas

[permalink] [raw]

Subject: Re: [Linux-fbdev-devel] [PATCH] vt: Delay the update of the visible framebuffer console

---

Jordan Crouse wrote:
> This is a patch that delays updating the visible framebuffer console
> until the other consoles have been initialized in order to avoid losing
> output lines. This problem was discovered when loading a framebuffer driver
> as a module. Comments welcome.
>
> Jordan
>
>
> ------------------------------------------------------------------------
>
> [PATCH] vt: Delay the update of the visible framebuffer console
>
> From: David Hollister <[email protected]>
>
> This patch delays the update of the visible framebuffer console until
> all other consoles have been initialized in order to avoid losing
> information. This only seems to be a problem with modules, not with
> built-in drivers.

Looks okay except for one point...

>
> Signed-off-by: David Hollister <[email protected]>
> Signed-off-by: Jordan Crouse <[email protected]>
> ---
>
> drivers/char/vt.c | 22 ++++++++++++++--------
> 1 files changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/char/vt.c b/drivers/char/vt.c
> index acc5d47..30f0f24 100644
> --- a/drivers/char/vt.c
> +++ b/drivers/char/vt.c
> @@ -2700,9 +2700,11 @@ int take_over_console(const struct consw
> if (!vc || !vc->vc_sw)
> continue;
>
> - j = i;
> - if (CON_IS_VISIBLE(vc))
> + if (CON_IS_VISIBLE(vc)) {
> + j = i;
> save_screen(vc);
> + }
> +
> old_was_color = vc->vc_can_do_color;
> vc->vc_sw->con_deinit(vc);
> vc->vc_origin = (unsigned long)vc->vc_screenbuf;
> @@ -2718,17 +2720,21 @@ int take_over_console(const struct consw
> */
> if (old_was_color != vc->vc_can_do_color)
> clear_buffer_attributes(vc);
> -
> - if (CON_IS_VISIBLE(vc))
> - update_screen(vc);
> }
> +
> printk("Console: switching ");
> if (!deflt)
> printk("consoles %d-%d ", first+1, last+1);
> - if (j >= 0)
> + if (j >= 0) {
> + struct vc_data *vc = vc_cons[j].d;
> +
> printk("to %s %s %dx%d\n",
> - vc_cons[j].d->vc_can_do_color ? "colour" : "mono",
> - desc, vc_cons[j].d->vc_cols, vc_cons[j].d->vc_rows);
> + vc->vc_can_do_color ? "colour" : "mono",
> + desc, vc->vc_cols, vc->vc_rows);
> +
> + if (CON_IS_VISIBLE(vc))
> + update_screen(vc);
> + }
> else
> printk("to %s\n", desc);

If take_over_console() is called with parameter first = 0, last = 4, and
the visible console = 5, you get here instead...

Tony