intel/xrandr1.2: cannot resize for larger external monitor

[JM Ibanez]

Drew Parsons <dparsons at debian.org> writes:

> I'm experiencing this problem on an Intel 82852/855GM (IBM thinkpad
> R51). Using video-intel 2.0RC4 (Debian 1.9.94-1), xserver 1.3RC5
> (1.2.99.905-1), xrandr 1.2.0. 
>
> If I start X on the laptop alone with no external monitor plugged in, X
> configures itself to the laptop screen at 1024x768, which is fine.  I
> power down with S4 hibernate, resume back in the office and plug in the
> office monitor, which has a 1900x1200 resolution.  xrandr --auto detects
> the external monitor and connects to it, but only configures it at a
> resolution of 1280x1024.  It does not acknowledge the 1900x1200
> resolution.  
>
> Indeed, the log file reports the matter this way:
>
> (II) intel(0): Supported additional Video Mode:
> (II) intel(0): clock: 154.0 MHz   Image Size:  519 x 324 mm
> (II) intel(0): h_active: 1920  h_sync: 1968  h_sync_end 2000 h_blank_end
> 2080 h_border: 0
> (II) intel(0): v_active: 1200  v_sync: 1203  v_sync_end 1209 v_blanking:
> 1235 v_border: 0
> (II) intel(0): Serial No: MW7967390D3S
> (II) intel(0): Monitor name: DELL 2407WFP
> (II) intel(0): Ranges: V min: 56  V max: 76 Hz, H min: 30  H max: 83
> kHz, PixClock max 170 MHz
> (II) intel(0): EDID (in hex):
> (II) intel(0):  00ffffffffffff0010ac16a053334430
> (II) intel(0):  0a1101030e342178eeee91a3544c9926
> (II) intel(0):  0f5054a54b008180a940714fb3000101
> (II) intel(0):  010101010101283c80a070b023403020
> (II) intel(0):  360007442100001a000000ff004d5737
> (II) intel(0):  39363733393044335320000000fc0044
> (II) intel(0):  454c4c20323430375746500a000000fd
> (II) intel(0):  00384c1e5311000a2020202020200042
> ...
> (II) intel(0): Modeline "1280x1024"  109.00  1280 1368 1496 1712  1024
> 1027 1034 1063 -hsync +vsync
> (II) intel(0): Modeline "1600x1200"  161.00  1600 1712 1880 2160  1200
> 1203 1207 1245 -hsync +vsync
> (II) intel(0): Modeline "1152x864"  104.00  1152 1224 1344 1536  864 867
> 871 905 -hsync +vsync
> (II) intel(0): Modeline "1680x1050"  146.25  1680 1784 1960 2240  1050
> 1053 1059 1089 -hsync +vsync
> (II) intel(0): Modeline "1920x1200"  154.00  1920 1968 2000 2080  1200
> 1203 1209 1235 -hsync +vsync
> (II) intel(0): EDID vendor "DEL", prod id 40982
> (II) intel(0): Not using mode "1920x1200" (width too large for virtual
> size)
> (II) intel(0): Not using mode "1600x1200" (width too large for virtual
> size)
> (II) intel(0): Not using mode "1680x1050" (width too large for virtual
> size)
>
> So apparently the problem is with the virtual screen.  If I try to
> resize it with "xrandr --fb 1920x1200", then xrandr refuses, saying the
> maximum allowed size is 1280x1280.  I seem to be able to change this
> with "xrandr --fbmm 1920x1200" after which "xrandr --fb 1920x1200" does
> appear to work.  But then when I try to resize the display with "xrandr
> --output VGA --auto" in hope of now seeing the 1920x1200 mode, the
> server crashes hard.
>
> Upon restarting X (rebooting) with the external monitor plugged in, X
> does see the 1920x1200 mode which I can select with no further trouble.
>
> Is this a bug which needs reporting or am I misusing xrandr?

Personally, I've had to prod the X server with a "Virtual" in the Screen
section, as the following snippet:

Section "Screen"
        Identifier      "Default Screen"
        Device          "Intel Corporation 82852/855GM Integrated Graphics Device"
        Monitor         "Generic Monitor"
        DefaultDepth    24
        SubSection "Display"
                Depth           24
                Modes           "1024x768" "800x600" "640x480"
                Virtual         2464 900
        EndSubSection
EndSection

This is what --fb reflects. The new XRandR 1.2 bits calculates the
framebuffer size to be large enough to accomodate all modes of all
*connected* displays. That's why it works when you have it plugged in
when X starts up works, but not when you plug it in later.

I haven't really used xrandr --fb, so maybe that's a bug?

-- 
JM Ibanez
Software Architect
Orange & Bronze Software Labs, Ltd. Co.

jm at orangeandbronze.com
http://software.orangeandbronze.com/