Does anybody know how to read monitor's EDID information on Windows XP. I
have found some source code that basically calls int 10h. But I cannot call
int 10h on Windows XP. I did search DDK document and found some APIs to read
the EDID information. But I just don't know how to do that. Is there any
sample code showing how to do that? Please help me!

By the way, does anybody know the relationship between the Gamma value in
EDID (one byte) and the real gamma value... I could not figure how to
convert that BYTE value into real gamma value...

Thanks a lot,

-Lucy

Windows only provides you with a PnP ID of the monitor, which is derived
from EDID.
The rest can be done only by videocard-specific hackery, no standard ways.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
maxim@storagecraft.com
http://www.storagecraft.com

"lucy" <losemind@yahoo.com> wrote in message
news:%234nb9UreEHA.4092@TK2MSFTNGP10.phx.gbl...

"Maxim S. Shatskih" <maxim@storagecraft.com> wrote in message
news:OFewz3teEHA.3476@tk2msftngp13.phx.gbl...

There you go.

#include "windows.h"
#include "setupapi.h"
#include "initguid.h"
#include "stdio.h"

#define NAME_SIZE 128
#define PRINT(_x_) printf _x_

DEFINE_GUID (GUID_CLASS_MONITOR,
0x4d36e96e, 0xe325, 0x11ce, 0xbf, 0xc1, 0x08, 0x00, 0x2b, 0xe1,
0x03, 0x18);

static void
PlayWithDeviceInfo(
IN HDEVINFO devInfo,
IN PSP_DEVINFO_DATA devInfoData
)
{
HKEY hDevRegKey;
DWORD uniID[123];

if (SetupDiGetDeviceRegistryProperty(
devInfo,
devInfoData,
SPDRP_DEVICEDESC,//SPDRP_UI_NUMBER,
NULL,
(PBYTE)(&uniID),
sizeof(uniID),
NULL))
{
printf("UID: %s\n",uniID);
}
else {
printf("ERROR: %d\n",GetLastError());
}



hDevRegKey = SetupDiOpenDevRegKey(
devInfo,
devInfoData,
DICS_FLAG_GLOBAL,
0,
DIREG_DEV,
KEY_ALL_ACCESS);

if (hDevRegKey) {
LONG retValue,i;
DWORD dwType, AcutalValueNameLength= NAME_SIZE;

CHAR valueName[NAME_SIZE];

for (i = 0, retValue = ERROR_SUCCESS; retValue !=
ERROR_NO_MORE_ITEMS; i++)
{
unsigned char EDIDdata[1024];
DWORD j,edidsize=sizeof(EDIDdata);

retValue = RegEnumValue (
hDevRegKey,
i,
&valueName[0],
&AcutalValueNameLength,
NULL,//reserved
&dwType,
EDIDdata, // buffer
&edidsize); // buffer size

if (retValue == ERROR_SUCCESS )
{
if (!strcmp(valueName,"EDID")) {
printf("Found value EDID\n");
{

for (j=0;j<edidsize;j++) {
if (j %16 == 0) printf("\n");
printf("%02x ",EDIDdata[j]);
}
printf("\n");
}

break;
}
}
}

RegCloseKey(hDevRegKey);
}
else {
printf("ERROR:%d\n",GetLastError());
}

}
int EnumDevices()
{
HDEVINFO devInfo = NULL;
SP_DEVINFO_DATA devInfoData;
SP_DEVINFO_LIST_DETAIL_DATA devInfoSetDetailData;
ULONG i;

do
{

devInfo = SetupDiGetClassDevsEx(
&GUID_CLASS_MONITOR, //class GUID
NULL, //enumerator
NULL, //HWND
DIGCF_PRESENT, // Flags //DIGCF_ALLCLASSES|
NULL, // device info, create a new one.
NULL, // machine name, local machine
NULL);// reserved

if (NULL == devInfo)
{
//PrintWin32Error("SetupDiGetClassDevsEx");
break;
}

for (i=0;ERROR_NO_MORE_ITEMS != GetLastError();i++)
{

memset(&devInfoData,0,sizeof(devInfoData));
devInfoData.cbSize = sizeof(devInfoData);

if (SetupDiEnumDeviceInfo(devInfo,i,&devInfoData))
{
PlayWithDeviceInfo(devInfo,&devInfoData);
}
}

} while (FALSE);

return i;
}

int __cdecl main()
{
EnumDevices();
return 0;
}

-
Calvin Guan Software Engineer
ATI Technologies Inc. www.ati.com

Ouch! I forgot to put "Copyleft Calvin Guan"-
-
Calvin Guan Software Engineer
ATI Technologies Inc. www.ati.com

"Calvin Guan" <cguan@pleasenospam.ati.com> wrote in message
news:%235ikTsxeEHA.1036@TK2MSFTNGP10.phx.gbl...

"Calvin Guan" <cguan@pleasenospam.ati.com> wrote in message
news:%235ikTsxeEHA.1036@TK2MSFTNGP10.phx.gbl...

Dear Calvin,

Thank you so much. I did read out the EDID with your code. I really don't
understand your code. But anyway, here is the result after running it:

UID: StudioWorks 995E
Found value EDID

00 ff ff ff ff ff ff 00 1e 6d 4c 4a 01 01 01 01
00 0a 01 01 7e 25 1b aa e8 e0 59 a3 54 46 9b 24
10 48 4c ff ff 80 31 59 45 59 61 59 81 99 a9 4f
01 01 01 01 01 01 1a 4f 40 30 62 b0 32 40 40 c0
10 00 5e 06 11 00 00 1e 00 00 00 fd 00 32 a0 1e
60 15 00 0a 20 20 20 20 20 20 00 00 00 fc 00 53
74 75 64 69 6f 57 6f 72 6b 73 20 39 00 00 00 fc
00 39 35 45 0a 20 20 20 20 20 20 20 20 20 00 4c
00 00 00 00 ff ff ff ff ff 00 1e 6d 4c 4a 01 01
01 01 00 0a 01 01 7e 25 1b aa e8 e0 59 a3 54 46
9b 24 10 48 4c ff ff 80 31 59 45 59 61 59 81 99
a9 4f 01 01 01 01 01 01 1a 4f 40 30 62 b0 32 40
40 c0 10 00 5e 06 11 00 00 1e 00 00 00 fd 00 32
a0 1e 60 15 00 0a 20 20 20 20 20 20 00 00 00 fc
00 53 74 75 64 69 6f 57 6f 72 6b 73 20 39 00 00
00 fc 00 39 35 45 0a 20 20 20 20 20 20 20 20 20
Press any key to continue

But this is really not what I want, it is a whole screen of strange numbers.
From my understanding the EDID should have some manufactorer information,
Gamma value, display modes, etc. Do you mean I should find some detailed
specifications of these numbers and do some translation? I think I can find
some specifications if they are available to the public somewhere on the
Internet.

This is a great program and provides a nice start. Thank you so much. I
really apreciate that.

-Lucy

btw, did you use any DDK function in your above code?

Each time a child PDO (monitor) is enumerated by the videoport/miniport
combo, the port driver stores the Edid data into child's device registry
key, (Actually, it took me sometime to figure out in windbg) so that app can
use SetupAPI to read it.

It also contains standard/extended timing info, pixel clock, display
PhySize(not for projector though) and many other.

See this:
http://www.vesa.org/standards_faqs.html#EDID

I'm not sure if you have to be a member to access the doc. I bet you may
find the definition of EDID struct in open source community?

EDID can have extension block, i.e. CEA861 block in many plasma TV which is
not governed by VESA.

SetupDiXxx is documented in DDK.

You are very welcome.

Calvin
-
Calvin Guan Software Engineer
ATI Technologies Inc. www.ati.com

I found some code to interpret EDID data at
http://john.fremlin.de/programs/linux/read-edid/
You can compile 'parse-edid.c' from
http://john.fremlin.de/programs/linu...d-1.4.1.tar.gz
and then save the EDID data to a file which in turn has to be supplied to
'parse-edid.exe'

poltrone

"Calvin Guan" <cguan@pleasenospam.ati.com> schrieb im Newsbeitrag
news:e#w9dH8eEHA.592@TK2MSFTNGP11.phx.gbl...

Instead of RegEnumValue, why not just RegQueryValue(Ex) ("EDID") ?

"Calvin Guan" <cguan@pleasenospam.ati.com> wrote in message
news:%235ikTsxeEHA.1036@TK2MSFTNGP10.phx.gbl...

"Alexander Grigoriev" <alegr@earthlink.net> wrote in message
news:evNhG%238eEHA.3428@TK2MSFTNGP11.phx.gbl...
Points taken! I've very limited programming experience in user mode

Thanks,
Calvin
-
Calvin Guan Software Engineer
ATI Technologies Inc. www.ati.com

"Calvin Guan" <cguan@pleasenospam.ati.com> wrote in message
news:e%23w9dH8eEHA.592@TK2MSFTNGP11.phx.gbl...
Thank you very much! Now I understand. Have a nice weekend!

"poltrone" <nospam@nospam.net> wrote in message
news:eMhfBY8eEHA.3428@TK2MSFTNGP11.phx.gbl...
Hi poltrone,

This is a smart solution. That's great. Thank you very much. Yet after some
reading, I still could not find the interepreation for Gamma value which is
one BYTE in EDID...

I read 120 from my EDID of DELL 2001FP. But how does that 120 relate to
real-world Gamma value?

1.2? 2.2? etc.?

anybody has an idea?

Thank you