Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Wed, 4 Apr 2001 13:09:11 +0200 (MET DST) | From | Mikael Pettersson <> | Subject | Re: console.c unblank_screen problem |
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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:
Thanks for this patch. I've been using it on my Dell Latitude laptop for the last 10 days, and it has been a significant improvement.
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. Restarting X would only fix this temporarily, as the next resume would have the same problem. This does not occur with a 2.2 kernel or with the Accelerated-X server I used before.
With the patch: No problem after 10 days with frequent suspend/resume cycles. (2.4.2-ac24 + the patch)
[Alan, mind putting this in the next 2.4.3-ac? I've rediffed it against 2.4.3-ac2.]
/Mikael
--- linux-2.4.3-ac2/drivers/char/console.c.~1~ Wed Apr 4 12:15:28 2001 +++ linux-2.4.3-ac2/drivers/char/console.c Wed Apr 4 12:29:01 2001 @@ -2713,12 +2713,16 @@ 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); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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