Created attachment 126218 [details] output of dmesg with i915.debug=14 The displayport connection on my system works fine for the BIOS messages and with grub, but KMS does not detect the (still existing) connection. A VGA connection to the same display works perfectly at full resolution of 1920x1200. Deactivating KMS with i915.modeset=0 results in a working displayport connection at a mismatched resolution of 1600x1200 and using the vesa drivers (confirmed by unplugging the VGA cable). So I am pretty sure this is not an hardware issue. dmesg with i915.debug=14 shows this (full dump is attached): [ 3.368039] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:38:DP-1] [ 3.368042] [drm:intel_dp_detect] [CONNECTOR:38:DP-1] [ 3.387613] [drm:intel_dp_aux_ch] dp_aux_ch timeout status 0x501500c8 [ 3.392029] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:38:DP-1] status updated from 3 to 2 [ 3.392032] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:38:DP-1] disconnected [ 3.392036] [drm:drm_setup_crtcs] [ 3.392067] [drm:drm_enable_connectors] connector 30 enabled? yes [ 3.392070] [drm:drm_enable_connectors] connector 33 enabled? no [ 3.392072] [drm:drm_enable_connectors] connector 38 enabled? no some time later we see this: [ 24.824069] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:38:DP-1] [ 24.824072] [drm:intel_dp_detect] [CONNECTOR:38:DP-1] [ 24.842179] [drm:intel_dp_get_dpcd] DPCD: 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 [ 24.842182] [drm:intel_dp_get_dpcd] Display Port TPS3 support: source no, sink no [ 24.842185] [drm:intel_dp_print_rates] source rates: 162000, 270000 [ 24.842186] ------------[ cut here ]------------ [ 24.842226] WARNING: CPU: 0 PID: 2309 at /build/linux-a2WvEb/linux-4.4.0/drivers/gpu/drm/i915/intel_dp.c:150 intel_dp_max_link_bw.isra.7+0x2d/0x50 [i915]() [ 24.842227] invalid max DP link bw val 2, using 1.62Gbps similar blocks are repeated a few times. The DPCD data is invalid, somehow the communication failed again. To me it looks like the aux channel reads give an invalid result. Strangely, the BIOS and grub are both able to communicate with the display using the very same connection only a few seconds earlier. Maybe the readout does not work if the connection is already established? Maybe there are different data rates for the aux channel? Hardware: Lenovo ThinkCentre M58 DMI: LENOVO 7359W51/LENOVO, BIOS 5CKT49AUS 05/18/2009 Core(TM)2 Duo CPU E7300 @ 2.66GHz (family: 0x6, model: 0x17, steppi Chipset Q45, ICH10DO Display HP LA2405wg System: plain Ubuntu Mate 16.04, current kernel. The problem was exactly the same with Ubuntu 14.04 before. $ uname -a Linux minibox 4.4.0-36-generic #55-Ubuntu SMP Thu Aug 11 18:01:55 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux $ xrandr --verbose Screen 0: minimum 8 x 8, current 1920 x 1200, maximum 32767 x 32767 DP1 disconnected (normal left inverted right x axis y axis) Identifier: 0x42 Timestamp: 44604 Subpixel: unknown Clones: CRTCs: 0 1 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: Broadcast RGB: Automatic supported: Automatic, Full, Limited 16:235 audio: auto supported: force-dvi, off, auto, on HDMI1 disconnected (normal left inverted right x axis y axis) Identifier: 0x43 Timestamp: 44604 Subpixel: unknown Clones: VGA1 CRTCs: 0 1 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: aspect ratio: Automatic supported: Automatic, 4:3, 16:9 Broadcast RGB: Automatic supported: Automatic, Full, Limited 16:235 audio: auto supported: force-dvi, off, auto, on VGA1 connected primary 1920x1200+0+0 (0x47) normal (normal left inverted right x axis y axis) 518mm x 324mm Identifier: 0x44 Timestamp: 44604 Subpixel: unknown Gamma: 0.97:1.0:0.98 Brightness: 0.98 Clones: HDMI1 CRTC: 0 CRTCs: 0 1 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: EDID: 00ffffffffffff0022f04a2801010101 0e15010468342078ee9ec5a6564b9a25 135054210800814081809500a940b300 d1c0010101017d4b80a072b02d4088c8 360006442100001c000000fd00323f18 4c14000a202020202020000000fc004c 41323430350a202020202020000000ff 00434e34313134304336340a20200090 1920x1200 (0x47) 193.250MHz -HSync +VSync *current +preferred h: width 1920 start 2056 end 2256 total 2592 skew 0 clock 74.56KHz v: height 1200 start 1203 end 1209 total 1245 clock 59.88Hz 1920x1080 (0xa4) 148.500MHz -HSync -VSync h: width 1920 start 2008 end 2052 total 2200 skew 0 clock 67.50KHz v: height 1080 start 1084 end 1089 total 1125 clock 60.00Hz 1600x1200 (0xa5) 162.000MHz +HSync +VSync h: width 1600 start 1664 end 1856 total 2160 skew 0 clock 75.00KHz v: height 1200 start 1201 end 1204 total 1250 clock 60.00Hz 1680x1050 (0xa6) 146.250MHz -HSync +VSync h: width 1680 start 1784 end 1960 total 2240 skew 0 clock 65.29KHz v: height 1050 start 1053 end 1059 total 1089 clock 59.95Hz 1280x1024 (0xa7) 108.000MHz +HSync +VSync h: width 1280 start 1328 end 1440 total 1688 skew 0 clock 63.98KHz v: height 1024 start 1025 end 1028 total 1066 clock 60.02Hz 1440x900 (0xa8) 106.500MHz -HSync +VSync h: width 1440 start 1520 end 1672 total 1904 skew 0 clock 55.93KHz v: height 900 start 903 end 909 total 934 clock 59.89Hz 1280x960 (0xa9) 108.000MHz +HSync +VSync h: width 1280 start 1376 end 1488 total 1800 skew 0 clock 60.00KHz v: height 960 start 961 end 964 total 1000 clock 60.00Hz 1024x768 (0xaa) 65.000MHz -HSync -VSync h: width 1024 start 1048 end 1184 total 1344 skew 0 clock 48.36KHz v: height 768 start 771 end 777 total 806 clock 60.00Hz 800x600 (0xab) 40.000MHz +HSync +VSync h: width 800 start 840 end 968 total 1056 skew 0 clock 37.88KHz v: height 600 start 601 end 605 total 628 clock 60.32Hz 640x480 (0xac) 25.200MHz -HSync -VSync h: width 640 start 656 end 752 total 800 skew 0 clock 31.50KHz v: height 480 start 490 end 492 total 525 clock 60.00Hz VIRTUAL1 disconnected (normal left inverted right x axis y axis) Identifier: 0x45 Timestamp: 44604 Subpixel: no subpixels Clones: CRTCs: 2 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter:
Created attachment 126219 [details] Xorg.0.log
I suspect this could be fixed by commit 82f2b4aca8fd90476fc3fd1786d107163ab17201 Author: Ville Syrjälä <ville.syrjala@linux.intel.com> Date: Thu May 4 21:15:30 2017 +0300 drm/i915: Fix rawclk readout for g4x Please re-test with that (looks like it should be included in 4.12-rc2)
based on last comment, seems to be fixed. Since there is no response from submitter will close bug as fixed. if the problem appears under the latest configuration please open a new bug and add logs
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