2 Replies Latest reply on Jul 30, 2018 1:02 PM by Intel Corporation

    Blanking from Custom Resolution differs from EDID Data

    bernd_s

      Hi,

       

      the video blanking from my HDMI differs from the EDID settings.

       

      The EDID Data which was received by Windows is correct:

      I checked the EDID Data which was received by DDC on both sides (Display EEPROM and Windows with MonInfo an other tools).

      > Resolution (HACT/VACT) 1280x480

      > Pixelclock: 40,480

      > HFP: 70

      > HPW / HSW: 15

      > HBP: 1

      > VFP: 11
      > VPW/VSW: 1
      > VBP: 2
      Now I check the Videotimings of the HDMI Signal (buildin function of my HDMI receiver) and the blanking parameters differs from the EDID data:

      > HFP: 1 (instead of 70 like windows received)

      > HPW / HSW: 69 (instead of 15 like windows received)

      > HBP: 16 (instead of 1 like windows received)

      > VFP: 12 (instead of 11 like windows received)

      > VBP: 1 (instead of 2 like windows received)

       

      Because of the high difference to the original values the TCON can't sync anymore and the display stays black.

      Some Resolutions work fine, some not. Also tested on a Linux system where the resolution works fine.

       

      Why are the parameters different? Windows bug or driver bug? What are the "rules to observer" to get almost the blanking parameters I need? The absolute exact values are not neccesary because the TCON can compensate a few percent.

       

      I'm using

      Intel(R) HD Graphics 520

      Driver Version: 21.20.16.4678

      Operating System: Windows* 7 Professional (6.1.7601)

       

      Thank you!