On Wed, Mar 20, 2013 at 05:36:21PM +1100, Trent W. Buck wrote:
> Jason White <[email protected]> writes:
>
> > The only relevant error I found in the kernel log is:
> > Mar 20 15:05:58 jdc kernel: [23207.760016] [drm] nouveau 0000:40:00.0: DDC
> > responded, but no EDID for DVI-I-2
>
> FWIW... IIRC EDID (and DCC?) are the way the computer asks the monitor
> "hey, what resolutions do you support?" -- they are the reason we don't
> need to manually specify modelines in xfree86.conf anymore.
>
> If it can't talk EDID to DVI-I-2, I would expect a monitor plugged into
> it to either get a generic "hopefully works anywhere" VESA mode line
> 800x600.
>
> I once had an LG 2010 LCD monitor where over DVI-D, EDID worked fine,
> but over D-sub, it negotiated an incorrect modeline. I worked around it
> by manually specifying a "2048x1024twb" type modeline each time I
> connected the laptop to that monitor.
Over the years, I've had a few monitors with similar EDID problems -
including the LG TV currently connected to my MythTV box. Dunno if it's
the nvidia card, the nvidia driver, or the LG TV itself....both nvidia
and LG seem less than stringent when conforming to standards.
I have found that you can use get-edid from the read-edid package to
dump the EDID data to a file, and then tell X to use that.
e.g. in the Monitor section of /etc/X11/xorg.conf on my myth box, I
have:
Option "CustomEDID" "DFP-1:/etc/X11/LG-42LD560.edid.bin"
Package: read-edid
Version: 2.0.0-3.1
Installed-Size: 76
Description-en: hardware information-gathering tool for VESA PnP monitors
read-edid consists of two tools:
.
get-edid uses a VESA VBE 2 interrupt service routine request to read
a 128 byte EDID version 1 structure from your graphics card, which
retrieves this information from the monitor via the Data Display
Channel (DDC).
.
get-edid uses architecture-specific methods for querying the video
hardware (real-mode x86 instructions on i386, Open Firmware device
tree parsing on PowerMac) and is therefore only available for i386 and
powerpc architectures.
.
parse-edid parses this data structure and outputs data suitable for
inclusion into the XFree86 or X.org configuration file. It is available
for any architecture.
Homepage: http://www.polypux.org/projects/read-edid/
BTW, the package description says it only works for i386 and powerpc
architectures - however, i had no difficulty using it on debian amd64
(with both 32-bit and 64-bit libs installed)
IIRC (and i could be wrong coz it was a couple of years ago), i had to
run it from a virtual console, without X started.
craig
--
craig sanders <[email protected]>
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