<div dir="ltr">Thank you for your reply. I took your advice and tried it. None of it really surprises me.<div><br></div><div>The problem seems pretty simple. There is simply nothing in the EDID that mentions that it's a 4096x2160 monitor. From looking at the code, I don't see any possible code path that would allow it to somehow discover a mode higher than what the EDID reports. Even if I did hit the code path that infers new modes, the function valid_inferred_mode will reject any resolution that's higher. Is there a mechanism for discovering these higher modes that I'm missing?</div><div><br></div><div>I'm willing to work on a patch that would make this monitor "just work". What I'm interested in is what a patch for this would even look like. I assume this would need to be added as a "quirk" since the EDID is factually wrong.</div><div><br></div><div>Here's the relevant logs:</div><div><br></div><div><div>[ 52.333372] [drm:drm_detect_monitor_audio [drm]] Monitor has basic audio support</div><div>[ 52.333382] [drm:drm_add_display_info [drm]] non_desktop set to 0</div><div>[ 52.333395] [drm:drm_add_edid_modes [drm]] ELD monitor 31MU97</div><div>[ 52.333402] [drm:drm_add_edid_modes [drm]] ELD size 32, SAD count 1</div><div>[ 52.333410] [drm:drm_add_display_info [drm]] non_desktop set to 0</div><div>[ 52.333496] [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:98:DP-4] probed modes :</div><div>[ 52.333506] [drm:drm_mode_debug_printmodeline [drm]] Modeline 95:"3840x2160" 60 533280 3840 3848 3992 4000 2160 2214 2219 2222 0x48 0x9</div><div>[ 52.333515] [drm:drm_mode_debug_printmodeline [drm]] Modeline 107:"3840x2160" 30 266640 3840 3848 3992 4000 2160 2214 2219 2222 0x40 0x9</div><div>[ 52.333523] [drm:drm_mode_debug_printmodeline [drm]] Modeline 114:"1920x1080" 60 148500 1920 2008 2052 2200 1080 1084 1089 1125 0x40 0x5</div><div>[ 52.333531] [drm:drm_mode_debug_printmodeline [drm]] Modeline 122:"1920x1080" 60 148500 1920 2008 2052 2200 1080 1084 1089 1125 0x40 0x5</div><div>[ 52.333539] [drm:drm_mode_debug_printmodeline [drm]] Modeline 126:"1920x1080" 60 148352 1920 2008 2052 2200 1080 1084 1089 1125 0x40 0x5</div><div>[ 52.333547] [drm:drm_mode_debug_printmodeline [drm]] Modeline 118:"1600x900" 60 108000 1600 1624 1704 1800 900 901 904 1000 0x40 0x5</div><div>[ 52.333555] [drm:drm_mode_debug_printmodeline [drm]] Modeline 116:"1280x1024" 60 108000 1280 1328 1440 1688 1024 1025 1028 1066 0x40 0x5</div><div>[ 52.333563] [drm:drm_mode_debug_printmodeline [drm]] Modeline 115:"1152x864" 60 81579 1152 1216 1336 1520 864 865 868 895 0x0 0x6</div><div>[ 52.333572] [drm:drm_mode_debug_printmodeline [drm]] Modeline 117:"1280x720" 60 74250 1280 1390 1430 1650 720 725 730 750 0x40 0x5</div><div>[ 52.333579] [drm:drm_mode_debug_printmodeline [drm]] Modeline 123:"1280x720" 60 74250 1280 1390 1430 1650 720 725 730 750 0x40 0x5</div><div>[ 52.333587] [drm:drm_mode_debug_printmodeline [drm]] Modeline 127:"1280x720" 60 74176 1280 1390 1430 1650 720 725 730 750 0x40 0x5</div><div>[ 52.333595] [drm:drm_mode_debug_printmodeline [drm]] Modeline 108:"1024x768" 60 65000 1024 1048 1184 1344 768 771 777 806 0x40 0xa</div><div>[ 52.333603] [drm:drm_mode_debug_printmodeline [drm]] Modeline 106:"800x600" 60 40000 800 840 968 1056 600 601 605 628 0x40 0x5</div><div>[ 52.333611] [drm:drm_mode_debug_printmodeline [drm]] Modeline 131:"720x480" 60 27027 720 736 798 858 480 489 495 525 0x40 0xa</div><div>[ 52.333619] [drm:drm_mode_debug_printmodeline [drm]] Modeline 124:"720x480" 60 27000 720 736 798 858 480 489 495 525 0x40 0xa</div><div>[ 52.333627] [drm:drm_mode_debug_printmodeline [drm]] Modeline 128:"640x480" 60 25200 640 656 752 800 480 490 492 525 0x40 0xa</div><div>[ 52.333635] [drm:drm_mode_debug_printmodeline [drm]] Modeline 97:"640x480" 60 25175 640 656 752 800 480 490 492 525 0x40 0xa</div><div>[ 52.333641] [drm:drm_mode_debug_printmodeline [drm]] Modeline 125:"640x480" 60 25175 640 656 752 800 480 490 492 525 0x40 0xa</div></div><div><br></div><div><br></div><div><br></div><div>Here's my parsed EDID:</div><div><br></div><div><div> header: 00 ff ff ff ff ff ff 00 </div><div> vendor/product identification: 1e 6d e7 76 01 01 01 01 01 18 </div><div> edid struct version/revision: 01 04 </div><div>basic display parameters/features: b5 3c 22 78 9e </div><div> color characteristics: e9 d5 aa 50 34 b6 25 0e 50 54 </div><div> established timings: 21 08 00 </div><div> standard timing identification: 71 40 81 80 81 c0 a9 c0 d1 c0 01 01 01 01 01 01 </div><div> detailed timing 0: 50 d0 00 a0 f0 70 3e 80 08 90 65 0c 6d 55 21 00 00 1a </div><div> detailed timing 1: 28 68 00 a0 f0 70 3e 80 08 90 65 0c 6d 55 21 00 00 1a </div><div> detailed timing 2: 00 00 00 fd 00 38 3d 1e 87 38 00 0a 20 20 20 20 20 20 </div><div> detailed timing 3: 00 00 00 fc 00 33 31 4d 55 39 37 0a 20 20 20 20 20 20 </div><div> extensions: 02 </div><div> checksum: af </div><div><br></div><div>Monitor</div><div> Model name............... 31MU97</div><div> Manufacturer............. GSM</div><div> Product code............. 30439</div><div> Module serial number..... 16843009</div><div> Serial number............ n/a</div><div> Manufacture date......... 2014, ISO week 1</div><div> EDID revision............ 1.4</div><div> Input signal type........ Digital</div><div> VESA DFP 1.x supported... Yes</div><div> Display type............. Undefined</div><div> Screen size.............. 600 mm x 340 mm (27.2 in)</div><div> Power management......... Standby </div><div> Extension blocks......... 2</div><div><br></div><div>Color characteristics</div><div> Default color space...... sRGB</div><div> Display gamma............ 2.20</div><div> Red chromaticity......... Rx 0.667 - Ry 0.314</div><div> Green chromaticity....... Gx 0.205 - Gy 0.712</div><div> Blue chromaticity........ Bx 0.147 - By 0.056</div><div> White point (default).... Wx 0.313 - Wy 0.329</div><div><br></div><div>Timing characteristics</div><div> Horizontal scan range.... 30 - 135 kHz</div><div> Vertical scan range...... 56 - 61 Hz</div><div> Video bandwidth.......... 560 MHz</div><div> GTF standard............. Not Supported</div><div> Preferred timing......... Yes</div><div> Native/preferred timing.. 3840x2160p at 60Hz (16:9)</div><div> Modeline............... "3840x2160" 533.280 3840 3848 3992 4000 2160 2214 2219 2222 +hsync -vsync</div><div><br></div><div>Standard timings supported</div><div> 640 x 480p @ 60Hz - IBM VGA</div><div> 800 x 600p @ 60Hz - VESA</div><div> 1024 x 768p @ 60Hz - VESA</div><div> 1152 x 864p @ 60Hz - VESA STD</div><div> 1280 x 1024p @ 60Hz - VESA STD</div><div> 1280 x 720p @ 60Hz - VESA STD</div><div> 1600 x 900p @ 60Hz - VESA STD</div><div> 1920 x 1080p @ 60Hz - VESA STD</div><div><br></div><div> cea extension header: 02 03 12 71 </div><div> data block collection: 45 10 04 03 01 00 23 09 07 07 83 01 00 00 </div><div> detailed timing descriptor 000: 02 3a 80 18 71 38 2d 40 58 2c 45 00 b8 6f 21 00 00 1e </div><div> padding: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 </div><div> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 </div><div> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 </div><div> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 </div><div> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 </div><div> checksum: 44 </div><div><br></div><div>CEA-861 Information</div><div> Revision number.......... 3</div><div> IT underscan............. Not supported</div><div> Basic audio.............. Supported</div><div> YCbCr 4:4:4.............. Supported</div><div> YCbCr 4:2:2.............. Supported</div><div> Native formats........... 1</div><div> Detailed timing #1....... 1920x1080p at 60Hz (16:9)</div><div> Modeline............... "1920x1080" 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync</div><div><br></div><div>CE video identifiers (VICs) - timing/formats supported</div><div> CEA Mode 16: 1920 x 1080p @ 60Hz</div><div> CEA Mode 04: 1280 x 720p @ 60Hz</div><div> CEA Mode 03: 720 x 480p @ 60Hz</div><div> CEA Mode 01: 640 x 480p @ 60Hz</div><div> CEA Mode 00: 0 x 0i @ 0Hz</div><div><br></div><div>CE audio data (formats supported)</div><div> LPCM 2-channel, 16/20/24 bit depths at 32/44.1/48 kHz</div><div><br></div><div>CEA speaker allocation data</div><div> Channel configuration.... 2.0</div><div> Front left/right......... Yes</div><div> Front LFE................ No</div><div> Front center............. No</div><div> Rear left/right.......... No</div><div> Rear center.............. No</div><div> Front left/right center.. No</div><div> Rear left/right center... No</div><div> Front left/right wide.... No</div><div> Front left/right high.... No</div><div> Top center............... No</div><div> Front center high........ No</div><div><br></div><div><br></div><div><br><div><br></div><div>I'm willing to write a patch, but I'm wondering what it should look like.</div><div dir="ltr"><br><div class="gmail_quote"><div dir="ltr">On Mon, Sep 24, 2018 at 1:49 AM Jani Nikula <<a href="mailto:jani.nikula@linux.intel.com" target="_blank">jani.nikula@linux.intel.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Sat, 22 Sep 2018, Brian Vincent <<a href="mailto:brainn@gmail.com" target="_blank">brainn@gmail.com</a>> wrote:<br>
> I have a LG 31MU97-B monitor. My understanding is that EDID does not have<br>
> a way to report itself as a 4096x2160 monitor, so it reports itself as a<br>
> 3840x2160 monitor. The mode that it actually supports for it's native<br>
> resolution that I've been using looks like this:<br>
<br>
A dmesg with drm.debug=14 might prove useful in figuring out what's<br>
actually going on. Without the user provided mode.<br>
<br>
BR,<br>
Jani.<br>
<br>
<br>
-- <br>
Jani Nikula, Intel Open Source Graphics Center<br>
</blockquote></div></div></div></div></div>