It’s not perfect, but I had am improved experience with the lapdock hdmi from Angstrom BBB-eMMC-flasher-2013.09.04.img.xz by setting these modelines in /etc/X11/xorg.conf in the Monitor section.
Modeline “1360x768@60” 84.50 1360 1392 1712 1744 768 783 791 807 +hsync +vsync
Modeline “1280x720@50” 74.25 1280 1720 1760 1980 720 725 730 750 +hsync +vsync
Then, pick the resolution using the GUI tool System → Preferences → Monitors tool.
dmesg on this 2013.09.04 version with Atrix lapdock shows that the EDID native resolution is rejected as invalid:
I have a raspberry pi and a altrix 4g lapdock also, and it works perfectly.
Will the /etc/X11/xorg.conf file that I have on the pi have the “current” values that are known for the lapdock, or is there somewhere else that would show the true “current” modelines that are being used?
If so, I could post them here for you.
jerry
Hi Jerry. From within xterm, please post the result of:
`
xrandr --verbose
`
From outside of xterm, like via SSH or serial console, this works on BBB-provided Angstrom to allow xrandr to connect to the X server (probably different on Raspbian):
export XAUTHORITY=ls /var/run/gdm/auth-for-root-*/database`
export DISPLAY=:0.0
xrandr --verbose
`
There is a new release coming that will resolve this known issue. You could also try other SW distributions that are listed on the Wiki. I know Fedora for example works.
Gerald
Can you point us to some BBB HDMI driver source repositories or changelogs about this? Is it the same section of code (rockchip driver and/or hdmi-core.c, hdmi-lcdc.o) mentioned in this thread? Freaktab Forums - FreakTab
I look forward to an Angstrom-based version that fits on 2GB eMMC with a newer (3.9+, maybe even 3.13) kernel. I’d be happy to test any such pre-built kernels.
Roland, here it is:
Screen 0: minimum 1366 x 768, current 1366 x 768, maximum 1366 x 768
default connected 1366x768+0+0 (0x77) normal (normal) 0mm x 0mm
Identifier: 0x76
Timestamp: 49636
Subpixel: unknown
Clones:
CRTC: 0
CRTCs: 0
Transform: 1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
filter:
1366x768 (0x77) 0.0MHz *current
h: width 1366 start 0 end 0 total 1366 skew 0 clock 0.0KHz
v: height 768 start 0 end 0 total 768 clock 0.0Hz
Thanks! Unfortunately, I was hoping there’d be non-zero “start… end … total … clock” values shown here, revealing timing data that could be used in a Modeline statement 
re:
1366x768 (0x77) 0.0MHz *current h: width 1366 start 0 end 0 total 1366 skew 0 clock 0.0KHz v: height 768 start 0 end 0 total 768 clock 0.0Hz
Is utility “xvidtune” from package “x11-xserver-utils” present on your Pi? Can you check to see if it shows the HSyncStart, HSyncEnd, HTotal, pixel clock, etc values?