https://bugs.freedesktop.org/show_bug.cgi?id=109336

Bug ID: 109336 Summary: gma500_gfx misdetects LVDS-1 as connected causing black screen Product: DRI Version: unspecified Hardware: x86-64 (AMD64) OS: Linux (All) Status: NEW Severity: minor Priority: medium Component: DRM/other Assignee: dri-devel@lists.freedesktop.org Reporter: dominik@greysector.net

On a Thecus N5550 NAS box (Intel Atom D2550/Cedarview platform), the gma500_gfx driver detects LVDS-1 output as connected (it's not):

Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:36:LVDS-1] status updated from unknown to connected

Only VGA-1 is connected, but that's detected correctly. This causes black screen after kernel loads the driver. Adding video=LVDS-1:d to the kernel command line works around the issue.

The kernel version is 4.19.13-300.fc29.x86_64 (Fedora 29). Kernel output with drm.debug=0xe:

Jan 13 13:15:08 kernel: [drm:psb_intel_opregion_setup [gma500_gfx]] Public ACPI methods supported Jan 13 13:15:08 kernel: [drm:psb_intel_opregion_setup [gma500_gfx]] ASLE supported Jan 13 13:15:08 kernel: [drm:psb_intel_init_bios [gma500_gfx]] Using VBT from OpRegion: $VBT CEDARVIEW d Jan 13 13:15:08 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 0:"1024x768" 0 65000 1024 1048 1184 1344 768 771 777 806 0x8 0xa Jan 13 13:15:08 kernel: [drm:psb_intel_init_bios [gma500_gfx]] No SDVO device info is found in VBT Jan 13 13:15:08 kernel: [drm:psb_intel_init_bios [gma500_gfx]] EDP timing in vbt t1_t3 2000 t8 10 t9 2000 t10 500 t11_t12 5000 Jan 13 13:15:08 kernel: [drm:psb_intel_init_bios [gma500_gfx]] VBT reports EDP: Lane_count 1, Lane_rate 6, Bpp 18 Jan 13 13:15:08 kernel: [drm:psb_intel_init_bios [gma500_gfx]] VBT reports EDP: VSwing 0, Preemph 0 Jan 13 13:15:08 kernel: [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). Jan 13 13:15:08 kernel: [drm] No driver support for vblank timestamp query. Jan 13 13:15:08 kernel: [drm:drm_do_probe_ddc_edid [drm]] drm: skipping non-existent adapter intel drm LVDSDDC_C Jan 13 13:15:08 kernel: [drm:cdv_intel_dp_init [gma500_gfx]] i2c_init DPDDC-B Jan 13 13:15:08 kernel: [drm:cdv_intel_dp_aux_ch [gma500_gfx]] dp_aux_ch timeout status 0x51440064 Jan 13 13:15:08 kernel: [drm:cdv_intel_dp_i2c_aux_ch [gma500_gfx]] aux_ch failed -110 Jan 13 13:15:08 kernel: [drm:cdv_intel_dp_aux_ch [gma500_gfx]] dp_aux_ch timeout status 0x51440064 Jan 13 13:15:08 kernel: [drm:cdv_intel_dp_i2c_aux_ch [gma500_gfx]] aux_ch failed -110 Jan 13 13:15:08 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] Jan 13 13:15:08 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:34:VGA-1] Jan 13 13:15:08 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:34:VGA-1] status updated from unknown to connected Jan 13 13:15:09 kernel: [drm:drm_add_display_info [drm]] non_desktop set to 0 Jan 13 13:15:09 kernel: [drm:drm_add_edid_modes [drm]] ELD: no CEA Extension found Jan 13 13:15:09 kernel: [drm:drm_add_display_info [drm]] non_desktop set to 0 Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:34:VGA-1] probed modes : Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 46:"1920x1200" 60 154000 1920 1968 2000 2080 1200 1203 1209 1235 0x48 0x9 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 48:"1600x1200" 60 162000 1600 1664 1856 2160 1200 1201 1204 1250 0x40 0x5 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 50:"1680x1050" 60 146250 1680 1784 1960 2240 1050 1053 1059 1089 0x40 0x6 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 55:"1280x1024" 75 135000 1280 1296 1440 1688 1024 1025 1028 1066 0x40 0x5 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 47:"1280x1024" 60 108000 1280 1328 1440 1688 1024 1025 1028 1066 0x40 0x5 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 49:"1152x864" 75 108000 1152 1216 1344 1600 864 865 868 900 0x40 0x5 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 56:"1024x768" 75 78750 1024 1040 1136 1312 768 769 772 800 0x40 0x5 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 57:"1024x768" 60 65000 1024 1048 1184 1344 768 771 777 806 0x40 0xa Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 58:"800x600" 75 49500 800 816 896 1056 600 601 604 625 0x40 0x5 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 51:"800x600" 60 40000 800 840 968 1056 600 601 605 628 0x40 0x5 Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 52:"640x480" 75 31500 640 656 720 840 480 481 484 500 0x40 0xa Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 53:"640x480" 60 25175 640 656 752 800 480 490 492 525 0x40 0xa Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 54:"720x400" 70 28320 720 738 846 900 400 412 414 449 0x40 0x6 Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:36:LVDS-1] Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:36:LVDS-1] status updated from unknown to connected Jan 13 13:15:09 kernel: [drm:drm_do_probe_ddc_edid [drm]] drm: skipping non-existent adapter intel drm LVDSBLC_B Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:36:LVDS-1] probed modes : Jan 13 13:15:09 kernel: [drm:drm_mode_debug_printmodeline [drm]] Modeline 59:"1024x768" 60 65000 1024 1048 1184 1344 768 771 777 806 0x8 0xa Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:39:DVI-D-1] Jan 13 13:15:09 kernel: [drm:drm_do_probe_ddc_edid [drm]] drm: skipping non-existent adapter intel drm HDMIB Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:39:DVI-D-1] status updated from unknown to disconnected Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:39:DVI-D-1] disconnected Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:41:DP-1] Jan 13 13:15:09 kernel: [drm:cdv_intel_dp_aux_ch [gma500_gfx]] dp_aux_ch timeout status 0x51440064 Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:41:DP-1] status updated from unknown to disconnected Jan 13 13:15:09 kernel: [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] [CONNECTOR:41:DP-1] disconnected Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] connector 34 enabled? yes Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] connector 36 enabled? yes Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] connector 39 enabled? no Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] connector 41 enabled? no Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] looking for cmdline mode on connector 34 Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] looking for preferred mode on connector 34 0 Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] found mode 1920x1200 Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] looking for cmdline mode on connector 36 Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] looking for preferred mode on connector 36 0 Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] found mode 1024x768 Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] picking CRTCs for 4096x4096 config Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] desired mode 1920x1200 set on crtc 29 (0,0) Jan 13 13:15:09 kernel: [drm:drm_setup_crtcs [drm_kms_helper]] desired mode 1024x768 set on crtc 31 (0,0) Jan 13 13:15:09 kernel: [drm:cdv_get_max_backlight [gma500_gfx]] LVDS Panel PWM value is 0! Jan 13 13:15:09 kernel: [drm:cdv_get_max_backlight [gma500_gfx]] LVDS Panel PWM value is 0! Jan 13 13:15:09 kernel: [drm] Initialized gma500 1.0.0 20140314 for 0000:00:02.0 on minor 0 Jan 13 13:16:17 kernel: [drm:drm_helper_hpd_irq_event [drm_kms_helper]] [CONNECTOR:34:VGA-1] status updated from connected to connected Jan 13 13:16:17 kernel: [drm:drm_helper_hpd_irq_event [drm_kms_helper]] [CONNECTOR:39:DVI-D-1] status updated from disconnected to connected Jan 13 13:16:17 kernel: [drm:cdv_intel_dp_aux_ch [gma500_gfx]] dp_aux_ch timeout status 0x51440064 Jan 13 13:16:17 kernel: [drm:drm_helper_hpd_irq_event [drm_kms_helper]] [CONNECTOR:41:DP-1] status updated from disconnected to disconnected Jan 13 13:16:37 kernel: [drm:drm_helper_hpd_irq_event [drm_kms_helper]] [CONNECTOR:34:VGA-1] status updated from connected to connected Jan 13 13:16:37 kernel: [drm:drm_helper_hpd_irq_event [drm_kms_helper]] [CONNECTOR:39:DVI-D-1] status updated from connected to connected Jan 13 13:16:37 kernel: [drm:cdv_intel_dp_aux_ch [gma500_gfx]] dp_aux_ch timeout status 0x51440064 Jan 13 13:16:37 kernel: [drm:drm_helper_hpd_irq_event [drm_kms_helper]] [CONNECTOR:41:DP-1] status updated from disconnected to disconnected