Samsung 900NF DDC problem

[Vedran Rodic]

Hi.

I guess Samsung monitors can be problematic :)

Xorg (latest git) doesn't find any modes for my monitor, it settles
for 1024x768 @60Hz (this the mode for the laptop panel on my X60 that
I'm attaching the monitor to).

get-edid gets my monitor DDC data, but with a clear warning:

The EDID data should not be trusted as the VBE call failed
EDID claims 255 more blocks left
EDID blocks left is wrong.
Your EDID is probably invalid.

get-edid|parse-edid however returns a perfectly valid monitor entry:

        # EDID version 1 revision 2
Section "Monitor"
        # Block type: 2:0 3:fd
        # Block type: 2:0 3:fc
        Identifier "S/M 900NF"
        VendorName "___"
        ModelName "S/M 900NF"
        # Block type: 2:0 3:fd
        HorizSync 30-110
        VertRefresh 50-160
        # Max dot clock (video bandwidth) 240 MHz
        # Block type: 2:0 3:fc
        # Block type: 2:0 3:ff
        # DPMS capabilities: Active off:yes  Suspend:yes  Standby:yes

        Mode    "1280x1024"     # vfreq 85.024Hz, hfreq 91.146kHz
                DotClock        157.500000
                HTimings        1280 1328 1488 1728
                VTimings        1024 1025 1028 1072
                Flags   "+HSync" "+VSync"
        EndMode
        # Block type: 2:0 3:fd
        # Block type: 2:0 3:fc
        # Block type: 2:0 3:ff
EndSection

Windows uses this edid without problems.

I've removed the DDC_checksum check from ./hw/xfree86/ddc/xf86DDC.c,
and now it works with Xorg like a charm. Obviously this "fix" is not
correct, but I'm wondering what to do:

1. Add a quirks mode to the DDC code, or
2. Check if the data in EDID is sane, and use even and checksum isn't correct.

What to do?

Thanks,
Vedran