[Openchrome-users] problem with Syncmaster wide monitor

[Alex Roitman]

Jelle and John,

On Thu, 2007-09-27 at 22:40 +0200, Jelle de Jong wrote: 
> I believe this will help you, I have a 940BW:
> 
> execute the following command:
> gtf 1680 1050 60 -x
> 
> result: (remove the _60 part)
> Modeline "1680x1050"  147.14  1680 1784 1968 2256  1050 1051 1054 1087
> -HSync +Vsync

I cannot seem to get this mode, as the X log says that my monitor
cannot do dotclock higher than 140.

Now bear with me just a little bit. I have the manual (on CD ROM)
that came with the monitor. In the Specifications section it says:

    Maximum Pixel Clock
    146 MHz (Analog,Digital)

And yet X tells that 140 is the max. Can it be that X is wrong?
Can I override this?

Further, in the preset mode list it has:

Mode            H Freq(kHz)  V Freq(Hz)  Pixel Clock(MHz)  Sync(H/V)
VESA,1680X1050  65,290       59,954      146,250           -/+


Which also happens to be:
  $ cvt 1680 1050 60
# 1680x1050 59.95 Hz (CVT 1.76MA) hsync: 65.29 kHz; pclk: 146.25 MHz
Modeline "1680x1050_60.00"  146.25  1680 1784 1960 2240  1050 1053 1059
1089 -hsync +vsync

But when I tried using this I fail:
(II) VIA(0): ViaValidMode: Validating shura0 (146250)
(II) VIA(0): ViaModePrimaryVGAValid
(II) VIA(0): Not using mode "shura0" (mode clock too high)

So the manual lists the mode with dotclock 146.25 while saying that
the max dotclock is 146, and the X says the max is 140. What a mess.


To complicate the matters, the openchrome driver manual via(4) says
that not all dotclocks are supported:
... 108.0,  108.28,  122.0,  122.726,  135.0,  148.5, ...

I am at a loss then why the 119 Mhz happens to run.
As I said in the previous mail, I think I do get the 1680x1050 mode
but it is a reduced blanking cvt mode:

   $ cvt -r 1680 1050 60

# 1680x1050 59.88 Hz (CVT 1.76MA-R) hsync: 64.67 kHz; pclk: 119.00 MHz
Modeline "1680x1050R"  119.00  1680 1728 1760 1840  1050 1053 1059 1080
+hsync -vsync

Now that seems to run, but the width does not fit as I said before.

> Some extra commands that can help you solve problems:
> xdpyinfo | grep resolution

  $ xdpyinfo | grep -A 12 \#0
screen #0:
  dimensions:    1680x1050 pixels (445x278 millimeters)
  resolution:    96x96 dots per inch
  depths (7):    24, 1, 4, 8, 15, 16, 32
  root window id:    0x47
  depth of root window:    24 planes
  number of colormaps:    minimum 1, maximum 1
  default colormap:    0x20
  default number of colormap cells:    256
  preallocated pixels:    black 0, white 16777215
  options:    backing-store NO, save-unders NO
  largest cursor:    32x32
  current input event mask:    0xfa0033


If I take a screenshot with e.g. GIMP, it shows the full 1680x1050 pixel
desktop, but the actual screen shows only part of this.


Any insights on this ugly set of problems?
Thanks for the help,
Alex