Using DSI to HDMI Adapter with BSP 3.0b2

Technical Support
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1

I’m using Colibri iMX8QPX on Iris carrier board with DSI to HDMI Adapter.

This works correctly with previous version using meta-fsl-bsl-release/toradex-sumo-4.14.78-1.0.0_ga-bringup, but no longer with the latest meta-toradex* BSP release 3.0b2.

Changing to fsl-imx8qxp-colibri-dsihdmi-eval-v3.dtb causes lots of kernel stack traces during boot:

[    2.116665] imx-drm display-subsystem: bound imx-drm-dpu-bliteng.2 (ops dpu_bliteng_ops)
[    2.125115] imx-drm display-subsystem: bound imx-dpu-crtc.0 (ops dpu_crtc_ops)
[    2.132659] imx-drm display-subsystem: bound imx-dpu-crtc.1 (ops dpu_crtc_ops)
[    2.140153] ------------[ cut here ]------------
[    2.144792] WARNING: CPU: 2 PID: 1 at /work/build/build/tmp/work-shared/colibri-imx8x/kernel-source/drivers/gpu/drm/drm_bridge.c:155 drm_bridge_detach+0x44/0x50
[    2.159155] Modules linked in:
[    2.162222] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.14.117-0+ge43e3a26e1b7 #1
[    2.169720] Hardware name: Toradex Colibri iMX8QXP/DX with LT8912 MIPI-DSI 2 HDMI bridge (DT)
[    2.178260] task: ffff80007a3b8000 task.stack: ffff000008048000
[    2.184191] PC is at drm_bridge_detach+0x44/0x50
[    2.188814] LR is at drm_encoder_cleanup+0x28/0xa0
[    2.193616] pc : [<ffff0000086e5be4>] lr : [<ffff0000086e9218>] pstate: 60000045
[    2.201019] sp : ffff00000804ba90
[    2.204341] x29: ffff00000804ba90 x28: 0000000000000000 
[    2.209659] x27: 0000000000000000 x26: 0000000000000001 
[    2.214985] x25: ffff0000093ab960 x24: ffff000008fcc598 
[    2.220310] x23: ffff80007aa7c800 x22: ffff000008fcc1e0 
[    2.225636] x21: ffff80007aa7c800 x20: 0000000000000000 
[    2.230961] x19: ffff80007aa7c030 x18: 00000000fffffffd 
[    2.236286] x17: 0000000000000000 x16: 0000000000000000 
[    2.241612] x15: 0000000000000001 x14: ffffffffffffffff 
[    2.246938] x13: ffff80007afd1d07 x12: ffff80007afd1d04 
[    2.252263] x11: 0000000000000038 x10: 0101010101010101 
[    2.257588] x9 : 0000000000000002 x8 : 0000000000000002 
[    2.262914] x7 : ffff0000090c0d70 x6 : 000000000000008c 
[    2.268239] x5 : 0000000000000090 x4 : 0000000000000000 
[    2.273564] x3 : 0000000000000040 x2 : 0000000000000000 
[    2.278890] x1 : 0000000000000000 x0 : ffff80007aa7c030 
[    2.284217] Call trace:
[    2.286667] Exception stack(0xffff00000804b950 to 0xffff00000804ba90)
[    2.293115] b940:                                   ffff80007aa7c030 0000000000000000
[    2.300965] b960: 0000000000000000 0000000000000040 0000000000000000 0000000000000090
[    2.308808] b980: 000000000000008c ffff0000090c0d70 0000000000000002 0000000000000002
[    2.316655] b9a0: 0101010101010101 0000000000000038 ffff80007afd1d04 ffff80007afd1d07
[    2.324498] b9c0: ffffffffffffffff 0000000000000001 0000000000000000 0000000000000000
[    2.332343] b9e0: 00000000fffffffd ffff80007aa7c030 0000000000000000 ffff80007aa7c800
[    2.340188] ba00: ffff000008fcc1e0 ffff80007aa7c800 ffff000008fcc598 ffff0000093ab960
[    2.348032] ba20: 0000000000000001 0000000000000000 0000000000000000 ffff00000804ba90
[    2.355878] ba40: ffff0000086e9218 ffff00000804ba90 ffff0000086e5be4 0000000060000045
[    2.363722] ba60: ffff80007aa7c030 ffff80007afb2e18 ffffffffffffffff ffff000008fcc1e0
[    2.371567] ba80: ffff00000804ba90 ffff0000086e5be4
[    2.376455] [<ffff0000086e5be4>] drm_bridge_detach+0x44/0x50
[    2.382128] [<ffff0000086e9218>] drm_encoder_cleanup+0x28/0xa0
[    2.387979] [<ffff00000870a8f4>] imx_nwl_dsi_bind+0x104/0x178
[    2.393737] [<ffff000008720bb8>] component_bind_all+0xf8/0x260
[    2.399583] [<ffff000008705fb8>] imx_drm_bind+0x1e0/0x2f8
[    2.404994] [<ffff000008720824>] try_to_bring_up_master+0x14c/0x1a8
[    2.411275] [<ffff000008720918>] component_add+0x98/0x160
[    2.416687] [<ffff0000087110b0>] dpu_bliteng_probe+0x20/0x30
[    2.422362] [<ffff000008728758>] platform_drv_probe+0x58/0xb8
[    2.428120] [<ffff0000087268d4>] driver_probe_device+0x204/0x2c0
[    2.434140] [<ffff000008726a48>] __driver_attach+0xb8/0xc0
[    2.439640] [<ffff000008724b1c>] bus_for_each_dev+0x6c/0xa8
[    2.445224] [<ffff0000087260c8>] driver_attach+0x20/0x28
[    2.450550] [<ffff000008725dcc>] bus_add_driver+0x1dc/0x208
[    2.456138] [<ffff000008727688>] driver_register+0x60/0xf8
[    2.461636] [<ffff0000087286ac>] __platform_driver_register+0x44/0x50
[    2.468095] [<ffff000009561a58>] dpu_bliteng_driver_init+0x1c/0x24
[    2.474287] [<ffff000008083c08>] do_one_initcall+0x38/0x11c
[    2.479873] [<ffff000009500cd4>] kernel_init_freeable+0x17c/0x210
[    2.485982] [<ffff000008e4727c>] kernel_init+0x10/0xfc
[    2.491129] [<ffff000008084e90>] ret_from_fork+0x10/0x18
[    2.496459] ---[ end trace a28a4ec5ff94382e ]---
[    2.501126] imx-drm display-subsystem: failed to bind mipi_dsi@56228000 (ops imx_nwl_dsi_component_ops): -517
[    2.511280] imx-drm display-subsystem: master bind failed: -517
2

Hi @sapiippo

Could you provide the exact version ( uname -a ) of the software of your module?
Have you made any changes to the software?

It will be helpful if you can share the complete dmesg log ( dmesg > dmesg.txt ) in a text file?

Thanks and best regards,
Jaski

3

Linux b2qt-colibri-imx8x 4.14.117-0+ge43e3a26e1b7 #1 SMP PREEMPT Tue Sep 24 08:42:16 UTC 2019 aarch64 aarch64 aarch64 GNU/Linux

This is a Boot2Qt image that’s based on the 3.0b2, kernel and u-boot parts are unmodified, Qt has been added to the image.

link text

4

Same behaviour also with the Toradex Console Image Colibri iMX8X (3.0b2 | 2019-08-30 | 99.24 MB)link text

5

Didn’t think to check if there are multiple versions of the adapter. Mine is V1.0 and the dtb is now configured for V1.1 only. I’m guess this would be the cause.

6

Yes, the DSI to HDMI adapter V1.0A is obsolete and no longer supported out-of-the-box. That said it can be made to work again with a hard-coded resolution with the following device tree patch:

diff --git a/arch/arm64/boot/dts/freescale/fsl-imx8qxp-colibri-dsihdmi-eval-v3.dts b/arch/arm64/boot/dts/freescale/fsl-imx8qxp-colibri-dsihdmi-eval-v3.dts
index 3ebbcef280ad..44cd3ca53804 100644
--- a/arch/arm64/boot/dts/freescale/fsl-imx8qxp-colibri-dsihdmi-eval-v3.dts
+++ b/arch/arm64/boot/dts/freescale/fsl-imx8qxp-colibri-dsihdmi-eval-v3.dts
@@ -60,40 +60,53 @@
 &i2c0_mipi_lvds0 {
 	status = "okay";
 
-	/* DSI to HDMI Adapter V1.1A */
-	i2c-switch@70 {
-		compatible = "nxp,pca9540";
-		#address-cells = <1>;
-		#size-cells = <0>;
-		reg = <0x70>;
-		i2c-mux-idle-disconnect;
-
-		i2c_sw0: i2c-sw@0 {
-			#address-cells = <1>;
-			#size-cells = <0>;
-			reg = <0>;
-
-			/* DDC/EDID */
+	/* DSI to HDMI Adapter V1.0A */
+	lt8912@48 {
+		compatible = "lontium,lt8912";
+		hpd-gpios = <&gpio1 31 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_gpio_hpd>;
+		reg = <0x48>;
+
+		port {
+			lt8912_1_in: endpoint {
+				remote-endpoint = <&mipi_dsi_bridge1_out>;
+			};
 		};
 
-		i2c-sw@1 {
-			#address-cells = <1>;
-			#size-cells = <0>;
-			reg = <1>;
-
-			lt8912@48 {
-				compatible = "lontium,lt8912";
-				ddc-i2c-bus = <&i2c_sw0>;
-				hpd-gpios = <&gpio1 31 GPIO_ACTIVE_HIGH>;
-				pinctrl-names = "default";
-				pinctrl-0 = <&pinctrl_gpio_hpd>;
-				reg = <0x48>;
-
-				port {
-					lt8912_1_in: endpoint {
-						remote-endpoint = <&mipi_dsi_bridge1_out>;
-					};
-				};
+		display-timings {
+			native-mode = <&timing1>;
+
+			timing0: timing0 {
+				clock-frequency = <74250000>;
+				hactive = <1280>;
+				vactive = <720>;
+				hfront-porch = <110>;
+				hsync-len = <40>;
+				hback-porch = <220>;
+				vfront-porch = <5>;
+				vsync-len = <5>;
+				vback-porch = <20>;
+				hsync-active = <0>;
+				vsync-active = <0>;
+				de-active = <0>;
+				pixelclk-active = <0>;
+			};
+
+			timing1: timing1 {
+				clock-frequency = <148500000>;
+				hactive = <1920>;
+				vactive = <1080>;
+				hfront-porch = <88>;
+				hsync-len = <44>;
+				hback-porch = <148>;
+				vfront-porch = <4>;
+				vsync-len = <5>;
+				vback-porch = <36>;
+				hsync-active = <0>;
+				vsync-active = <0>;
+				de-active = <0>;
+				pixelclk-active = <0>;
 			};
 		};
 	};