Dell P2217H EDID issue - Monitor or GPU?
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11-20-2016, 04:57 AM
Post: #1
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Dell P2217H EDID issue - Monitor or GPU?
Hi. I recently acquired a Dell P2217H. It has a maximum resolution of 1920x1080@60hz and 3 inputs: VGA, HDMI and DisplayPort.
Over HDMI, it works just fine at 1920x1080 as advertised. However, over VGA and DP it only display available resolutions up to 1680x1050. To make it work at 1920x1080, I have to add a custom resolution using CRU (or through Nvidia control panel) on Windows. With the little bit of knowledge I have, I decided to check the monitor's EDID. The problem is that the 1920x1080 resolution is defined in an extension block, and apparently my GPU cannot read the extension block through DP, only using HDMI. I was certain that this was a monitor issue until I read, in the CRU thread, that Nvidia driver has issues with extension blocks. And I only tested the monitor in 2 computers: My desktop (ASUS 1070 GTX) and my laptop (onboard Intel with a GeForce 840M, and I believe the VGA port is connected to the GeForce GPU). My question is: Is this likely a monitor issue and I should try to have Dell get me a working monitor, or this could just be the Nvidia issue? And why does it work through HDMI but not DP or VGA? Here's the output of edid-decode of the dump I made through HDMI Code: Extracted contents: Thanks in advance PS: Your nvidia driver patches and CRU saved me many times, thanks a lot for your time and effort. |
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11-20-2016, 07:28 PM
Post: #2
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RE: Dell P2217H EDID issue - Monitor or GPU?
Do you have the P2217 or the P2217H? The P2217 is 1680x1050, while the P2217H is 1920x1080. If you have the P2217H, then it has the wrong EDID. 1920x1080 should be the first detailed resolution, not 1680x1050.
NVIDIA does not have issues reading extension blocks, only overrides with no extension blocks. CRU 1.3 can now read extension blocks with NVIDIA. Does CRU show the monitor has an extension block with DisplayPort? The monitor might not have one. |
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11-20-2016, 11:23 PM
Post: #3
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RE: Dell P2217H EDID issue - Monitor or GPU?
(11-20-2016 07:28 PM)ToastyX Wrote: Do you have the P2217 or the P2217H? The P2217 is 1680x1050, while the P2217H is 1920x1080. If you have the P2217H, then it has the wrong EDID. 1920x1080 should be the first detailed resolution, not 1680x1050.It's the P2217H. Or at least it should be Pretty sure they took some P2217 skeletons and replaced the panel but messed up reprogramming the EDID. Anyway, the EDID I posted is the EDID I dumped through the HDMI port on Linux, and CRU indentifies the extension block when connected via HDMI: [Image: http://imgur.com/sS1KBoX] However, through DisplayPort it does not show up (full hd resolution added by me): [Image: http://imgur.com/Fawpt2C] So, Nvidia actually has no problems with this, and the monitor is simply not sending the extension block through DP / VGA ports then? |
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11-21-2016, 03:18 AM
Post: #4
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RE: Dell P2217H EDID issue - Monitor or GPU?
Well, now that I took I closer look to what I posted, it's pretty obvious:
Code: CEA extension block CRU also has (HDMI) at the end of the data block definition. So, it seems the GPU is ignoring the extension block when reading the EDID through VGA or DP since it's a HDMI-specific extension block, reasonably so. Did I get this right? |
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11-21-2016, 08:21 AM
Post: #5
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RE: Dell P2217H EDID issue - Monitor or GPU?
(11-20-2016 11:23 PM)saboya Wrote: [Image: http://imgur.com/Fawpt2C]That's likely the case. To know for sure, you have to reset it first. CRU will show you if the EDID has extension blocks. "No extension blocks" means the EDID has no extension blocks. "Default extension block" means the EDID has an extension block, but CRU couldn't read it. (11-21-2016 03:18 AM)saboya Wrote: CRU also has (HDMI) at the end of the data block definition. So, it seems the GPU is ignoring the extension block when reading the EDID through VGA or DP since it's a HDMI-specific extension block, reasonably so.No, it's not ignoring anything. Each port on the monitor has a separate EDID. HDMI requires an extension block to define HDMI support. DisplayPort and VGA don't need extension blocks, but they can use extension blocks to define more resolutions. |
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11-21-2016, 12:49 PM
Post: #6
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RE: Dell P2217H EDID issue - Monitor or GPU?
I see. Thanks for clarifying the situation for me. I'll get in touch with Dell to sort this out.
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