Volker Kuhlmann wrote: >> Hi, I have managed to partially configure the settings for an LCD >> monitor that is rated at 1440x900 @60Hz (from the manual's specs - an >> AOC 193FW). I did so by using SuSE's "Graphics Card & Monitor" tool in >> Yast. >> > > Good. > > >> This got me as far as getting 1440x900, but the only refresh >> options available (KDesktop > Display) are 50 and 55Hz. It doesn't look >> flash at 50, way better at 55Hz, and of course I want to be getting the >> rated 60Hz (hoping it looks even better). >> > > That KDE refresh selector is kind of a pointless feature. Why would you > ever switch down? Configure the system for one frequency and do it > right. It's made for CRT monitors anyway. > > With LCD monitors, there are 2 things to know: > > 1) The resolution (correct: number of pixels) has to always be exactly > the same as the number of pixels of the LCD panel, otherwise there is > serious loss of quality to the point of the whole monitor being useless. > So no choice here, the monitor comes with a number and that's it. > > 2) Because the delay of switching pixels of an LCD panel is so > astronomically high, there never will be any flicker caused by a > vertical refresh which is too low. Therefore this is basically a > pointless number; the monitor will probably be using internally what it > wants to anyway and there's nothing you can do about that. > However, the rate at which the data goes from the computer into the > monitor's frame buffer needs to be within the limit of the monitor's > input circuitry. As this has nothing to do with reducing flicker (as > with CRTs), you can put what you want, within the limit of course. > That's why 60Hz almost always gets you there. Of course someone could > make a really cheap fixed frequency input circuitry, in which case only > 60Hz will get you there (monitor will give sync error otherwise). > > Again: the refresh rate from computer to LCD monitor only has to match > the input circuitry of the monitor and has no effect on flicker of the > display. > > That was the background, now to the problem. > > When I look in the monitor model list under AOC, there are only what > looks like CRTs. Go for model "LCD", and pick a generic resolution and > 60Hz. That's all you should need to do, however, there's 1440x900 only > with 70Hz. Ok 2 options: try that first (make sure you use the test > function in SaX2, if you're left with an Xorg config with which the > monitor doesn't sync you're somewhat screwed). Next, still select > [EMAIL PROTECTED], and go into the Sync frequencies tab and reduce the upper > limit of vertical from 72 to 62. If that works, file a bug at > bugzilla.novell.com for openSUSE saying that [EMAIL PROTECTED] is needed in > the "--> LCD" list. > > Oh and you can ignore the "wrong sync frequencies will damage your > monitor" with LCDs. Though don't try and crank it, you're wasting your > time, the picture can't get any better. > > To find out the sync frequencies reliably, have the monitor tell you. If > it doesn't, you're into a bit of fudging. All these commands are > probably right: > > xwininfo -root (thanks Nick) > > xvidtune > > nvidia-settings (if you have an nvidia card and use the nvidia driver) > > It would be interesting to see if any of those give wrong values (the > monitor should always be right). If there is any doubt left, the > oscilloscope is definitely right. > > There should be no need to edit the Xorg config file with a text editor, > SaX2 ought to do it (and does for me). Of course if you prefer > $TEXTEDITOR go for it. > > Volker > I had followed the route via model=LCD,[EMAIL PROTECTED] and then edited the xorg.conf modelname and vendorname lines.
xwininfo -root (doesn't tell me anything on refresh rate?) xwininfo: Window id: 0x155 (the root window) (has no name) Absolute upper-left X: 0 Absolute upper-left Y: 0 Relative upper-left X: 0 Relative upper-left Y: 0 Width: 1440 Height: 900 Depth: 24 Visual Class: TrueColor Border width: 0 Class: InputOutput Colormap: 0x20 (installed) Bit Gravity State: NorthWestGravity Window Gravity State: NorthWestGravity Backing Store State: NotUseful Save Under State: no Map State: IsViewable Override Redirect State: no Corners: +0+0 -0+0 -0-0 +0-0 -geometry 1440x900+0+0 however both xvidtune and nvidia-settings are showing that I am on 60Hz so all good. Thanks for all the replies! 3 great commands I didn't know about. And I'm sure I'll get better picture as soon as I get a dvi extension and dispense with the vga cable it's currently running on. Roger
