Topic Title: ati/amd drivers not reading ddc/edid info from monitor
Topic Summary: windows detects monitor as default monitor
Created On: 09/24/2011 07:10 PM
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 09/24/2011 07:10 PM
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Cybot
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Joined: 07/05/2009

before i begin, some things to keep in mind,

monitor is plug and play, is vga only, and vga cable is non-detachable

http://www.viewsonic.pt/support/desktopdisplays/crtmonitors/graphicseries/gs790/#overview

also video card is an radeon hd 4670 agp 1Gb. card on a windows xp pro system running an AMD Athlon XP 2800+ CPU, System ram is 3Gb.

catalyst version is 11.8 and is unable to read ddc/edid info as well (actually it says my monitor doesn't support ddc, which is wrong.) ddc revision of monitor is 1.2 (acccording to data obtained by reading ddc/edid directly from monitor)

windows registry has the compatibleIDs set to *PNP09FF which i believe means it's being detected as a pnp monitor but device manager sets   it to default monitor

I recently had to do a clean install after a hard drive failed in my system, and after installing the latest AMD/ATI catalyst drivers, i noticed windows i not detecting my viewsonic GS790 monitor as pnp any more. infact a look in the registry under the hklm/..../device parameters/ has a BAD_EDID reg_binary setting filled in with just 00's.

the monitor used to be detected just fine. using a utility called moninfo, i was able to see the ddc/edid info just fine coming from the monitor. using powerstrip uing the monitor information utility, info from the registry was not able to be retrieved, as was stored edid data, when selecting read data from stored edid, a message apperred that read "valid edid data could not be obtained from windows or the display driver. ddc is not supported".  selecting read data directly from monitor edid/ddc, and the data is successfully displayed. there is no signs of edid corruption when it is read directly from the moitor, all info is correct and  as it should be. i plugged in my monitor into my i7/nvidia/win7x64 laptop and it detected as a pnp monitor.

the fact that i'm able to read the edid/ddc info directly from the monitor and that it is detected properly on another system, would seem to rule out the monitor itself or the vga cable as the culprit.

the culprit would seem to be the ATI/AMD drivers/catalyst 11.8 drivers. my monitor was detected in the past by my machine and by catalyst as being pnp, so i'm just mystified. the culprit could possibly by the video card, but i doubt it as it seems to be working properly, save for the ddc/edid thing. if anybody else knows how to solve this issue, help would be greatly appreciated.



Edited: 09/24/2011 at 08:57 PM by Cybot
 10/25/2011 01:25 AM
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grigp
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Joined: 10/25/2011

I have same problem with Compaq P1100 monitor and Sapphire 2600XT AGP video card (AMD Catalyst 10.9 AGP hotfix).

 11/25/2011 09:03 AM
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duedark
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I have the same problem. ATI HD 4350 1GB and VIEWSONIC VA703M I tried E71f TOO BUT STILL SAME .. !! I DONT HAVE THIS PROBLEM WITH NVIDIA !!

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