[PATCH] 2.4.3-ac9 console unblank at resume fix

From: Mikael Pettersson (mikpe@csd.uu.se)
Date: Wed Apr 18 2001 - 08:39:25 EST


Alan,

I think I've finally eliminated the X screen corruption my laptop
has been seeing at resume from suspend events.

The fix in -ac3 eliminated the corruption but left the console
blank if I exited X. The fix in -ac4 didn't actually work --
the corruptions resurfaced later. (Sorry about that.) I've tested
a lot of variations of it, but all had the same problem.

The new fix goes back to the original (exit early if not in text
mode), with one crucial change: console_blanked is NOT reset to zero.
This appears to have the desired effect: while X is running we
don't mess with the hardware, and the first unblank after X has
exited does the right thing. Works fine over here (so far..).
Patch below for -ac9, please apply.

[To recap: Dell Latitude, 2.4 kernel, XFree86-SVGA-3.3.6, APM,
no frame buffer device. After a few (1-3) days of use with
frequent suspend/resume cycles, the X screen would partially
wrap around after a resume. Restarting X would fix this temporarily,
but the next resume would see the same problem. Reboot, and I'd get
another few days before it happened again. 2.2 kernel was fine.]

/Mikael

--- linux-2.4.3-ac9/drivers/char/console.c.~1~ Wed Apr 18 13:50:00 2001
+++ linux-2.4.3-ac9/drivers/char/console.c Wed Apr 18 13:50:24 2001
@@ -2713,23 +2713,21 @@
                 printk("unblank_screen: tty %d not allocated ??\n", fg_console+1);
                 return;
         }
+ currcons = fg_console;
+ if (vcmode != KD_TEXT)
+ return; /* but leave console_blanked != 0 */
         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 (vcmode != KD_TEXT)
- return;
+ if (sw->con_blank(vc_cons[currcons].d, 0))
                 /* 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 : Mon Apr 23 2001 - 21:00:26 EST