5 Replies Latest reply on Apr 18, 2017 6:43 AM by donuts

    Unable to set desktop to 3840×2160 with Acer CB241HQK monitor over DVI

    donuts

      I have an AMD FirePro W5100. Windows 10 64-bit 1703, AMD driver version 22.19.157.3.

       

      Acer CB241HQK monitor, native resolution 3840×2160 pixels. It has DisplayPort, DVI and HDMI inputs. Connecting via DisplayPort, the desktop defaults to its native resolution at 60Hz. No problem there. Over DVI however, although the monitor supports 3840×2160@30Hz, the desktop comes up at 1920×1080@60Hz and AMD settings/display settings does not offer 3840×2160@30Hz as an option.

       

      When I try to create a custom resolution in Radeon/FirePro settings, even exactly matching the values given in the monitor's EDID detailed timing block (see below), it refuses to add the mode, saying "The custom resolution settings are not compatible with your display. Reconfigure your settings and try again."

       

      As you can see from the EDID info below, the monitor EDID does contain a detailed timing block for 3840×2160@30Hz, but the AMD driver seems to be ignoring that.

       

      So this seems to be a bug or inadequacy of the AMD driver. Is there any way I can override Radeon/FirePro Settings' refusal to accept any custom mode?

       

      Here is a hex dump of the EDID as read when connected to the monitor's DVI port via a DisplayPort-to-DVI passive adapter. Note that I have redacted my monitor's serial number.

      00 FF FF FF FF FF FF 00 04 72 99 04 XX XX XX XX

      2B 19 01 03 80 34 1D 78 2E E6 95 A3 54 4A 99 26

      0F 50 54 BF EF 80 81 C0 81 00 81 80 95 00 B3 00

      81 40 D1 C0 71 4F 04 74 00 30 F2 70 5A 80 B0 58

      8A 00 09 25 21 00 00 1E 00 00 00 FF 00 XX XX XX

      XX XX XX XX XX XX XX XX XX 0A 00 00 00 FD 00 17

      50 1E 63 1E 00 0A 20 20 20 20 20 20 00 00 00 FC

      00 41 63 65 72 20 43 42 32 34 31 48 51 4B 00 XX

       

      I used EEditZ to parse that and it reported:

       

      Established timings: (all except 720×400@85Hz and 1024×768i@87Hz)

      Standard timing:

      1280@60Hz 16:9, 1280@60Hz 16:10, 1280@60Hz 5:4, 1440@60Hz 16:10, 1680@60Hz 16:10, 1280@60Hz 4:3, 1920@60Hz 16:9, 1152@75Hz 4:3

       

      There is one detailed timing block which specifies a 3840×2160@30Hz mode:

      Pixel clock 297.00MHz

      H. active 3840, H. blank 560, H. front porch 176, H. sync width 88

      V active 2160, V blank 90, V front porch 8, V sync width 10