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Explorer
Explorer
465 Views
Registered: ‎09-06-2019

EDID parameter meanings

Hi,

I'm having trouble understanding what resolutions are supported by my EDID. I've used a parser to break down the DAT file but am confused to the differences between established, standard timing, and detailed timing. Are all resolutions that are present in each of the three categories supported? Or do supported resolutions need to be defined in each of the timing blocks mentioned above?

Thanks!!

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Moderator
Moderator
420 Views
Registered: ‎04-09-2019

Hello @badFITimage ,

Please note that, here Only 2 timing standards are there, those are Established and Standard Timings. Detailed Timing Descriptor is not a timing standard, It holds the 18 bytes of the information regarding the video defined in the above mentioned two timing standards. I recommend You to go through any EDID descriptor document.

Kindly, go through the sections from 3.8 to 3.10.3 in the EDID.pdf document. This document clearly addressed about the established and standard timing details, along with the detailed timing descriptor.

Hope it helps to You. Kindly let me know, If you face any problems to open the Link for the document.

With Regards,

Ashok.

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Explorer
Explorer
396 Views
Registered: ‎09-06-2019

Hi @ashokkum,

Thanks for providing the reference!

For further clarification, section 3.8 starts by mentioning the following:

The established timing block is a field of one-bit flags, which are used to indicate support for established VESA and other common timings in a very compact form. Other standardized timings can be described in the Standard Timings block defined in Section 3.9. Any timing can be described using the Detailed Timings block defined in Section 3.10.

The sections immediately following the one mentioned above go into further detail about the standard timings block and the detailed timing block. From information provided by the descriptor document it seems like since we are using a resolution that is defined in the standard display mode timing, SXGA (1280x1024@60), and as long as we enable that timing in the established timing it is not necessary to include/add further information in the standard/detailed timings block - is this correct?

For reference here is the EDID we are using:

 

	0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x4C, 0x2D, 0x61, 0x01, 0x00, 0x00, 0x00, 0x00, 
	0x14, 0x0E, 0x01, 0x03, 0x80, 0x22, 0x1B, 0x78, 0x2A, 0xEE, 0x91, 0xA3, 0x54, 0x4C, 0x99, 0x26, 
	0x0F, 0x50, 0x54, 0xBF, 0xEF, 0x00, 0x81, 0x80, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x64, 0x19, 0x00, 0x40, 0x41, 0x00, 0x26, 0x30, 0x18, 0x88, 
	0x36, 0x00, 0x52, 0x0E, 0x11, 0x00, 0x00, 0x18, 0x30, 0x2A, 0x00, 0x98, 0x51, 0x00, 0x2A, 0x40, 
	0x30, 0x70, 0x13, 0x00, 0x52, 0x0E, 0x11, 0x00, 0x00, 0x1E, 0x00, 0x00, 0x00, 0xFD, 0x00, 0x38, 
	0x4B, 0x1E, 0x51, 0x0E, 0x00, 0x0A, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0xFC, 
	0x00, 0x53, 0x79, 0x6E, 0x63, 0x4D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x0A, 0x20, 0x20, 0x00, 0xFD

 

 

When parsed using http://www.edidreader.com/ results in the following standard display mode information:

 

Thanks!

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Teacher
Teacher
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Registered: ‎06-16-2013

Hi @badFITimage 

 

I suggest you to make sure the behavior with your EDID on X Window, if possible.

You can see the detail behavior in your log file.

 

[Note]

Nowadays, standard video timing is for fail-safe, if anything. Also, it is rarely used any more without clear intentions.

I guess, your issue seems compatibility issue on your source device, if anything.

I suggest you to modify video timing as workaround, if you can modify video timing or behavior of video driver on source device.

 

Best regards,