Problem with EDID Data Retrival
Problem with EDID Data Retrival
- Subject: Problem with EDID Data Retrival
- From: "amber maheshwari" <email@hidden>
- Date: Thu, 19 Apr 2007 12:02:32 +0530
Hi all,
We are using i2cexample source code to read EDID data, source for the same is available at
http://darwinsource.opendarwin.org/Current/IOGraphics-179.2/tools/i2cexample.c
This programs read EDID data. But this particular program
is not able to read EDID data when two monitors are attached to "NVIDIA
Quadro FX 4500 / Nvidia GeForce 7300 GT "
Below are the machine details
Mac OS X 10.4.7
Processor 2 X 2.66 GHz Dual-Core Intel Xeon
Memory: 1 GB 667 MHz DDR2
PCI: NVIDIA Quadro FX 4500 DeviceID 0x009d / Nvidia GeForce 7300 GT
It reads EDID data correctly only when single monitor is attached.
When Dual monitors are connected the response obtained is not according to the display
ID calculated as given below:
///////
CGDirectDisplayID priDisplayID;
CGDirectDisplayID secDisplayID;
OSErr GetDisplayIDs()
{
CGDisplayCount num_displays;
CGDirectDisplayID* display_ids;
CGDisplayErr err = noErr;
err = CGGetActiveDisplayList(0, NULL, &num_displays);
if (err != CGDisplayNoErr || num_displays == 0)
return err;
display_ids = (CGDirectDisplayID*)malloc(sizeof(CGDirectDisplayID)*num_displays);
err = CGGetActiveDisplayList(num_displays, display_ids, &num_displays);
require_noerr(err,cleanup);
if (num_displays == 1)
{
priDisplayID = display_ids[0];
secDisplayID = 0;
free(display_ids);
return err;
}
if (CGMainDisplayID () == display_ids[0])
{
priDisplayID = display_ids[0];
secDisplayID = display_ids[1];
}
else
{
priDisplayID = display_ids[1];
secDisplayID = display_ids[0];
}
cleanup:
free(display_ids);
return err;
}
It gives random EDID Data like sometimes it gives same EDID for both the monitors irrespective of the port to which the monitor is connected.
Did anybody encountered similar situation before ?
Please comment.
Thanks and Regards,
Amber Maheshwari
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