On Wed, 4 Apr 2001 13:09:11 +0200 (MET DST), Mikael Petterson wrote:
> On Sun, 25 Mar 2001 18:40:03 +0200, Benjamin Herrenschmidt wrote:
>
> >There is a problem with the power management code for console.c
> >
> >The current code calls do_blank_screen(0); on PM_SUSPEND, and
> >unblank_screen() on PM_RESUME.
> >
> >The problem happens when X is the current display while putting the
> >machine to sleep. The do_blank_screen(0) code will do nothing as
> >the console is not in KD_TEXT mode.
> >However, unblank_screen has no such protection. That means that
> >on wakeup, the cursor timer & console blank timers will be re-enabled
> >while X is frontmost, causing the blinking cursor to be displayed on
> >top of X, and other possible issues.
> >
> >I hacked the following pacth to work around this. It appear to work
> >fine, but since the console code is pretty complex, I'm not sure about
> >possible side effects and I'd like some comments before submiting it
> >to Linus:
>...
> Before the patch: After a few days with a 2.4 kernel and RH7.0
> (XFree86-4.0.1-1 and XFree86-SVGA-3.3.6-33) the latop would
> misbehave at a resume event: when I opened the lid the screen would
> unblank and then after less than a second the entire screen would
> shift (wrap/rotate) left by about 40% of its width.
>...
> With the patch: No problem after 10 days with frequent suspend/resume
> cycles. (2.4.2-ac24 + the patch)
Correction: While the patch eliminated the X screen wrap problem at resume,
it caused a new problem: now when I exit X the console is left in a blanked
state. This seems to happen if at least one suspend/resume cycle has
occurred before X is terminated.
After some experimentation I came up with the patch below (vs. 2.4.3-ac3)
which _so_far_ behaves ok on my laptop. If the resume-while-in-X problems
resurface or not I won't know until after several more days of testing,
but at least the console is unblanked correctly again.
Does _anyone_ understand this code and its interactions with X? I'm lost...
/Mikael
--- linux-2.4.3-ac3/drivers/char/console.c.~1~ Thu Apr 5 15:57:36 2001
+++ linux-2.4.3-ac3/drivers/char/console.c Thu Apr 5 18:52:43 2001
@@ -2713,23 +2713,23 @@
printk("unblank_screen: tty %d not allocated ??\n", fg_console+1);
return;
}
- currcons = fg_console;
- if (vcmode != KD_TEXT) {
- console_blanked = 0;
- return;
- }
console_timer.function = blank_screen;
if (blankinterval) {
mod_timer(&console_timer, jiffies + blankinterval);
}
-
+ currcons = fg_console;
console_blanked = 0;
if (console_blank_hook)
console_blank_hook(0);
set_palette(currcons);
- if (sw->con_blank(vc_cons[currcons].d, 0))
+ if (sw->con_blank(vc_cons[currcons].d, 0)) {
+ if (vcmode != KD_TEXT)
+ return;
/* Low-level driver cannot restore -> do it ourselves */
update_screen(fg_console);
+ }
+ if (vcmode != KD_TEXT)
+ return;
set_cursor(fg_console);
}
-
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This archive was generated by hypermail 2b29 : Sat Apr 07 2001 - 21:00:18 EST