linux-surface
Display panel does not work occasionally
The SPX SQ1 display panel could not work correctly after a reboot. The display never shows back up again during system startup when switching from the efi framebuffer to drm/msm after a reboot.
This only happens after a reboot. For a cold startup, the display panel works well in msm drm mode.
Tested on the latest kernel Linux 6.15.3-1-surface+.
After a reboot, the panel-simple-dp-aux complains about failing to read EDID of the display panel in dmesg:
[ 9.213236] panel-simple-dp-aux aux-ae9a000.displayport-controller: Couldn't read EDID for ID; using conservative timings
[ 9.216775] msm_dpu ae01000.mdp: bound ae9a000.displayport-controller (ops msm_dp_display_comp_ops [msm])
...
[ 9.731211] panel-simple-dp-aux aux-ae9a000.displayport-controller: No display modes
[ 9.797642] [drm:msm_dp_panel_read_sink_caps [msm]] *ERROR* panel edid read failed
For a cold startup, the panel-simple-dp-aux is able to detect the EDID correctly:
[ 9.098128] panel-simple-dp-aux aux-ae9a000.displayport-controller: Detected LGD LP129WT112684 (0x0555)
[ 9.099579] msm_dpu ae01000.mdp: bound ae9a000.displayport-controller (ops msm_dp_display_comp_ops [msm])
The dmesg of a cold boot: 20250705-dmesg-cold-startup-1.txt
The dmesg after a reboot: 20250705-dmesg-after-reboot-1.txt
Update: just find something more weird. If I add "loglevel=8" to the kernel cmdline, the eDP panel is more likely[^1] to work (after a reboot). If I use any other loglevel (e.g. 3 or 7), the panel-simple-dp-aux driver fails to read the EDID (after a reboot). The kernel is compiled with CONFIG_DYNAMIC_DEBUG=y.
^1: sometimes eDP fails with max v_level reached, link training #1 failed.
[ 7.066072] panel-simple-dp-aux aux-ae9a000.displayport-controller: Detected LGD LP129WT112684 (0x0555)
[ 7.070776] msm_dpu ae01000.mdp: bound ae9a000.displayport-controller (ops msm_dp_display_comp_ops [msm])
[ 7.075468] adreno 2c00000.gpu: supply vdd not found, using dummy regulator
[ 7.076169] adreno 2c00000.gpu: supply vddcx not found, using dummy regulator
[ 7.079208] msm_dpu ae01000.mdp: bound 2c00000.gpu (ops a3xx_ops [msm])
[ 7.081156] Console: switching to colour dummy device 80x25
[ 7.081445] [drm:dpu_kms_hw_init:1173] dpu hardware revision:0x50010001
[ 7.083856] [drm] Initialized msm 1.12.0 for ae01000.mdp on minor 0
[ 7.084319] msm_dpu ae01000.mdp: [drm:adreno_request_fw [msm]] loaded qcom/a680_sqe.fw from new location
[ 7.084996] msm_dpu ae01000.mdp: [drm:adreno_request_fw [msm]] loaded qcom/a680_gmu.bin from new location
[ 7.086803] [drm] Loaded GMU firmware v2.2.264
[ 7.299103] Bluetooth: hci0: QCA Downloading qca/crnv01.bin
[ 7.368636] remoteproc remoteproc0: remote processor modem is now up
[ 7.414348] tun: Universal TUN/TAP device driver, 1.6
[ 7.440145] Bluetooth: hci0: QCA setup on UART is completed
[ 7.441311] [drm:msm_dp_ctrl_link_train [msm]] *ERROR* max v_level reached
[ 7.441429] [drm:msm_dp_ctrl_link_train [msm]] *ERROR* link training #1 failed. ret=-11
[ 7.463128] [drm:msm_dp_aux_isr [msm]] *ERROR* Unexpected DP AUX IRQ 0x01000000 when not busy
[ 7.463282] [drm:msm_dp_aux_isr [msm]] *ERROR* Unexpected DP AUX IRQ 0x01000000 when not busy
Update: If I comment out the GPIO 130 in the DTS, the problem appears to be gone, no more occasional panel disfunction, no more screen tear when switching from framebuffer mode to msm drm mode during boot. Since GPIO 130 is SOC_VDD_PANEL_EN, I guess that the problem may be caused by an unexpected transient loss of power of the display panel when switching from framebuffer mode to msm drm mode.
diff --git a/arch/arm64/boot/dts/qcom/sc8180x-surface-pro-x.dts b/arch/arm64/boot/dts/qcom/sc818
0x-surface-pro-x.dts
index f615edc5ffcf..1d6ba41f563c 100644
--- a/arch/arm64/boot/dts/qcom/sc8180x-surface-pro-x.dts
+++ b/arch/arm64/boot/dts/qcom/sc8180x-surface-pro-x.dts
@@ -943,10 +943,10 @@ panel {
compatible = "edp-panel";
no-hpd;
- enable-gpios = <&tlmm 130 GPIO_ACTIVE_HIGH>;
+ //enable-gpios = <&tlmm 130 GPIO_ACTIVE_HIGH>;
- pinctrl-names = "default";
- pinctrl-0 = <&panel_vdd_en_default_state>;
+ //pinctrl-names = "default";
+ //pinctrl-0 = <&panel_vdd_en_default_state>;
backlight = <&backlight>;