re-probing DDC/EDID

[perryh at pluto.rain.com]

Robert Noland <rnoland at FreeBSD.org> wrote:
> On Fri, 2009-05-22 at 15:18 -0700, perryh at pluto.rain.com wrote:
> > Robert Noland <rnoland at FreeBSD.org> wrote:
> > > On Thu, 2009-05-21 at 23:38 -0700, perryh at pluto.rain.com wrote:
> > > > Is there any way to re-probe the monitor's DDC/EDID while the
> > > > X server is running?
> > ...
> > > xrandr?
> >
> > That seems to return the set of resolutions probed at startup
> > (i.e. those of the old monitor):
>
> what driver are you using?

ATI, I think.  I'll append xorg.conf (with comments deleted,
to reduce its size a bit).

> Radeon or Intel *should* detect a changed display I think.
> You really shouldn't need to set modelines anymore.

When setting up the previous monitor -- and the one before that --
it seemed necessary to remove unusable modelines from xorg.conf,
else CtrlAlt+ and CtrlAlt- would set modes that produced a messed-
up display or a blank screen.  (The monitors' DDC reports -- or
-configure's interpretation of them -- apparently included modes
that would not actually work.)

> Do keep in mind that since the front buffer is created at startup
> time and can't currently be re-sized on the fly that you need to
> set the virtual screen size to the maximum that you intend to use
> or that will be the highest mode used (and displayed by xrandr).

I had expected something along those lines, which is why I didn't
expect to be able to _use_ 1920x1200 without restarting, but I'd
still expect to be able to rerun the probe of the monitor and get
the new report -- including the modelines that would have been
generated if I had been running that probe "for real".

============================ xorg.conf ============================

Section "ServerLayout"
	Identifier     "X.org Configured"
	Screen      0  "Screen0" 0 0
	InputDevice    "Mouse0" "CorePointer"
	InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"
	RgbPath      "/usr/X11R6/lib/X11/rgb"
	ModulePath   "/usr/X11R6/lib/modules"
	FontPath     "/usr/X11R6/lib/X11/fonts/misc/"
	FontPath     "/usr/X11R6/lib/X11/fonts/TTF/"
	FontPath     "/usr/X11R6/lib/X11/fonts/Type1/"
	FontPath     "/usr/X11R6/lib/X11/fonts/CID/"
	FontPath     "/usr/X11R6/lib/X11/fonts/75dpi/"
	FontPath     "/usr/X11R6/lib/X11/fonts/100dpi/"
EndSection

Section "Module"
	Load  "dbe"
	Load  "dri"
	Load  "extmod"
	Load  "glx"
	Load  "record"
	Load  "xtrap"
	Load  "freetype"
	Load  "type1"
EndSection

Section "InputDevice"
	Identifier  "Keyboard0"
	Driver      "kbd"
EndSection

Section "InputDevice"
	Identifier  "Mouse0"
	Driver      "mouse"
	Option	    "Protocol" "auto"
	Option	    "Device" "/dev/psm0"
	Option	    "ZAxisMapping" "4 5 6 7"
EndSection

Section "Monitor"
	Identifier   "Monitor0"
	VendorName   "BTC"
	ModelName    "LM-1702"
	Modeline "1280x1024"  108.00  1280 1328 1440 1688  1024 1025 1028 1066 +hsync +vsync
	Modeline "1024x768"    65.00  1024 1048 1184 1344   768  771  777  806 -hsync -vsync
	Modeline  "800x600"    40.00   800  840  968 1056   600  601  605  628 +hsync +vsync
	Modeline  "640x480"    25.20   640  656  752  800   480  490  492  525 -hsync -vsync
	Option	    "DPMS"
EndSection

Section "Device"
	Identifier  "Card0"
	Driver      "ati"
	VendorName  "ATI"
	BoardName   "3D Rage Pro AGP 1X/2X"
	ChipSet     "ati"
	ChipId      0x4742
	ChipRev     0x5c
	BusID       "PCI:1:0:0"
EndSection

Section "Screen"
	Identifier "Screen0"
	Device     "Card0"
	Monitor    "Monitor0"
	SubSection "Display"
		Viewport   0 0
		Depth     1
		Modes "1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Viewport   0 0
		Depth     4
		Modes "1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Viewport   0 0
		Depth     8
		Modes "1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Viewport   0 0
		Depth     15
		Modes "1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Viewport   0 0
		Depth     16
		Modes "1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Viewport   0 0
		Depth     24
		Modes "1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
EndSection