how to read monitor's EDID information?
lucy
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
Maxim S. Shatskih
from EDID.
The rest can be done only by videocard-specific hackery, no standard ways.
--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
ma...@storagecraft.com
http://www.storagecraft.com
"lucy" <lose...@yahoo.com> wrote in message
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Calvin Guan
news:OFewz3te...@tk2msftngp13.phx.gbl...
> 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.
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
Calvin Guan
"Calvin Guan" <cg...@pleasenospam.ati.com> wrote in message
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lucy
"Calvin Guan" <cg...@pleasenospam.ati.com> wrote in message
news:%235ikTsx...@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?
Calvin Guan
> understand your code. But anyway, here is the result after running it:
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 is a whole screen of strange numbers.
> From my understanding the EDID should have some manufactorer information,
> Gamma value, display modes, etc.
It also contains standard/extended timing info, pixel clock, display
PhySize(not for projector though) and many other.
> 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.
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.
> btw, did you use any DDK function in your above code?
SetupDiXxx is documented in DDK.
>Thank you so much. I
> really apreciate that.
You are very welcome.
Calvin
poltrone
http://john.fremlin.de/programs/linux/read-edid/
You can compile 'parse-edid.c' from
http://john.fremlin.de/programs/linux/read-edid/read-edid-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" <cg...@pleasenospam.ati.com> schrieb im Newsbeitrag
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Alexander Grigoriev
"Calvin Guan" <cg...@pleasenospam.ati.com> wrote in message
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Calvin Guan
news:evNhG%238eEH...@TK2MSFTNGP11.phx.gbl...
> Instead of RegEnumValue, why not just RegQueryValue(Ex) ("EDID") ?
Points taken! I've very limited programming experience in user mode;)
Thanks,
Calvin
lucy
Thank you very much! Now I understand. Have a nice weekend!
lucy
"poltrone" <nos...@nospam.net> wrote in message
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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