Jim McCarthy wrote:
The flashing screen problem indicates your monitor cannot support the
current screen resolution.
Not these monitors, they print a nice text message. I have a DELL 1801FP
(on that computer) and a DELL 1901FP on my KVM. Both are fairly good
LCD monitors.
Especially when it's often displaying something, when flashing.
The flashing is most likely a buggy driver.
Thanks Jim & Christopher for your help.
Just to confirm this, I would recommend navigating the "menu" buttons on the monitor(s) until you find the
"information" or "mode" data, which will report (on the LCD screen) "Hpixels x Vpixels x
V-Refresh" to which each monitor is trying to sync.
Screen says its running at [EMAIL PROTECTED] Hz, whether it's flashing or
not. Same as this one.
Back in the glory days of CRT monitors, best (flicker-free) performance was
found at high vertical refresh rates (e.g., 85Hz). But with LCDs, at least in
my experience (mainly with Viewsonic VP171b LCD displays), 60Hz vertical
refresh rate seems fine.
If the LCD monitor menu information indicates that X is trying to
"over-achieve" by working at a higher vertical refresh rate than the minimum
necessary (say 60Hz), here's what I'd do ...
Mine run at 75 Hz, thought the OSD recommends 60. This is not the
problem, Besides, the problem comes and goes as X is restarted
Multiplying Vpixels times V-refresh gives a lower limit on the horizontal sync frequency
needed to support that video mode (it's the "lower limit" because it includes
no overhead for anything besides actually refreshing lines on the screen) ... you'd
probably want to round upwards (by at least 5%, maybe 10% ?) the result of the
multiplication (or check what the LCD display itself reports in that mode when working
properly on a Windows PC :-).
Anyway, where I'm headed with this is: based on the Vpixels x V-Refresh mode
that you want from SL5.1 (for 1280x1024 say, 1024 x 60Hz = 61Khz ... call it
64KHz), you might try reducing the monitor top vertical frequency and top
horizontal frequency capability in the /etc/X11/Xorg.conf (or XF86config-4 )
file, to just slightly more than necessary for 1280 x 1024 x 60Hz, to prevent X
from trying to over-achieve in frequency terms ... 60Hz vertical should be less
demanding on video card RAM etc., compared to 72Hz or 75Hz or 80Hz or 85Hz.
For example:
Section "Monitor"
Identifier "Monitor0"
VendorName "Viewsonic"
ModelName "VP171b"
HorizSync 31.5-64 # units are KHz
VertRefresh 50.0-62.0 # units are Hz
Option "dpms"
EndSection
Interestingly, I don't have a monitor description.
Also (whether or not you find any value in the above suggestion), have you
looked in the /var/log file for X startup for any clues about what might be
going on ?
Many times. I've even diffed different logs, as I changed drivers.
--
Cheers
John
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