Joe Tseng wrote:
I inherited an ancient Dell Latitude C840 and recently installed CentOS 5.2 on it. It worked fine for the most part, but when I left it overnight and came back the next morning, the screen blacked out and wouldn't come back unless I did a hard reset. Even though I turned off all the power management settings and left it set like a desktop, the next morning after that it still blacked out. I thought maybe it'd come back if I switched from X to a virtual text console, but that didn't do the trick. Has anyone seen this and what do I do to fix it?
Is the machine still responsive? e.g. does the caps light key work? Or is it frozen solid?
I don't know how many laptops it affects but my previous Toshiba laptops had problems where if the screen went into power save mode about 70% of the time the only way to get it to turn back on was to either reboot the box or put it in suspend/sleep/hibernate and wake it up again. Toshiba said this was a common problem across vendors that used multiple cores in their laptops. Microsoft released a fix for it for XP about a year and a half ago(though as the fix was a specialized fix not a generic fix that was pushed out to users I didn't realize it until after I switched off of XP and onto Ubuntu, took a while until a version of Ubuntu came out that could suspend/resume on that system). I could not find any related fix for X11, so I just disabled screen blanking in the X server.
It's been a while and I don't have that laptop anymore but what I believe I did was add
Options "-DPMS"
To the monitor section of xorg.conf, see the man page for xorg.conf for other DPMS related options.
Of course that just turns off screen blanking/power off, if your system is crashing, that's another topic..
nate