Dual Display

From Variscite Wiki
Revision as of 18:56, 13 September 2018 by Admin (talk | contribs) (Created page with "[[Image:]][[Image:]][[Image:]][[Image:]][[Image:]][[Image:]][[Image:]]'''Dual Display on VAR-SOM-SOLO/DUAL / DART-MX6 : Android Application Tech Note.''' IMX6 platform is ca...")
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

[[Image:]][[Image:]][[Image:]][[Image:]][[Image:]][[Image:]][[Image:]]Dual Display on VAR-SOM-SOLO/DUAL / DART-MX6 : Android Application Tech Note.


IMX6 platform is capable of handling multiple displays. You can drive


See page : 15 - 19 http://cache.freescale.com/files/training/doc/ftf/2014/FTF-CON-F0119.pdf


Starting from Android 4.3 multiple displays are supported


DART-MX6 / Solo both have LVDS0 and LVDS1 output available on the development board.

VAR-DT6CustomBoard:

For both channels: LVDS0/1 - LVDS Clock +4 Data lanes are accessible via Carrier board Headers.

VAR-SOLOCustomBoard:

LVDS0 - LVDS Clock +4 Data lanes are accessible via Carrier board Headers.

LVDS1 - LVDS Clock +3 Data lanes are accessible via Carrier board Headers (only 18 bit LCD can be interfaced)


For maximum supported resolution and combination refer to

http://cache.freescale.com/files/training/doc/ftf/2014/FTF-CON-F0119.pdf age no 16.


The configuration can be like

  1. Clone display (Primary is always cloned)
  2. Independent display

In case of 1. The kernel will not register another framebuffer for 2nd panel, however clone internally from the SOC itself via IPU framebuffer driver from the interface specific drivers. Aka LDB, HDMI, RGB.


In case of 2. The kernel registers 2nd FB to the platform.


Use case Two LVDS - LVDS0 and LVDS1 port on SOLO

  • Hardware Setup

2 x LVDS Panel : https://www.variscite.com/products/accessories/vlcd-cap-gld-lvds/

Reference : https://www.variscite.com/wp-content/uploads/2017/12/VLCD-CAP-GLD-LVDS.pdf


Connect 1st panel to LVDS1 - which is enabled by default with the software. Connect straight LVDS panel header to LVDS1 as this doesn’t require special handling.


Connect 2nd panel to LVDS0 - which requires changes in the software.

This example uses identical LVDS panel however you can have asymmetric combination as well.


Top level setup should look like below [[Image:]]


[[Image:]]


Using wires connect LVDS0 to LVDS header in the LCD panel with following combination.

Pin to pin as shown in the below with color coded.


PIN
LVDS0
PIN - J16
 PIN PIN
LVDS LCD Panel Header
 PIN
1
 3.3 V 3.3 V
2
1
 VCC - 3V VCC - 3V
2
3
 GND GND
4
3
 GND GND
4
5
 LVDS0_TX0_N LVDS0_TX0_P
6
5
 RIN0_N RIN0_P
6
7
 GND LVDS0_TX1_N
8
7
 GND RIN1_N
8
9
 LVDS0_TX1_P GND
10
9
 RIN1_P GND
10
11
 LVDS0_TX2_N LVDS0_TX2_P
12
11
 RIN2_N RIN2_P
12
13
 GND LVDS0_CLK_N
14
13
 GND RCLK_N
14
15
 LVDS0_CLK_P GND
16
15
 RCLK_P GND
16
17
 LVDS0_TX3_N LVDS0_TX3_P
18
17
 5V_CC_Backlight 5V_CC_Backlight
18
19
 VCC_5V PWM_BACK_LIGHT
20
19
 PWM_INPUT GND
20

Note :

  • LVDS0 provides 3 lane but LCD just needs 2 lane LVDS input.
  • Be careful about PIN 19 of LVDS0 header, please make sure it is connected to PIN17 or PIN18 of the LCD panel header only. Connecting this pin to other pins of LCD or shorting to GND may cause permanent damage to LCD or board.

Software Changes for Multiple Display:

Android Oreo 8.0 and Android 7.1.2 :

  • Software Preparation for Dual Display (Two LVDS):
  1. U-Boot: On uboot you require below patch to be applied.

For Android 8.0: vendor/variscite/uboot-imx/

For Android 7.1.2: bootable/bootloader/uboot-imx/


diff --git a/board/variscite/mx6var_som/mx6var_som.c b/board/variscite/mx6var_som/mx6var_som.c

index 526a11f..729c966 100644

--- a/board/variscite/mx6var_som/mx6var_som.c

+++ b/board/variscite/mx6var_som/mx6var_som.c

@@ -907,7 +907,7 @@ static void setup_display(void) 

| IOMUXC_GPR2_BIT_MAPPING_CH1_SPWG

| IOMUXC_GPR2_DATA_WIDTH_CH1_18BIT

| IOMUXC_GPR2_BIT_MAPPING_CH0_SPWG

- | IOMUXC_GPR2_DATA_WIDTH_CH0_24BIT

+ | IOMUXC_GPR2_DATA_WIDTH_CH0_18BIT 

| IOMUXC_GPR2_LVDS_CH0_MODE_ENABLED_DI0

| IOMUXC_GPR2_LVDS_CH1_MODE_ENABLED_DI0;

writel(reg, &iomux->gpr[2]);

diff --git a/include/configs/mx6var_som.h b/include/configs/mx6var_som.h

index 1db7afb..b27f7ee 100644

--- a/include/configs/mx6var_som.h

+++ b/include/configs/mx6var_som.h

@@ -195,7 +195,7 @@

"video=mxcfb0:dev=ldb; " \

"fi; " \

"setenv bootargs ${bootargs} " \

-"video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off;\0"

+"video=mxcfb1:dev=ldb video=mxcfb2:off video=mxcfb3:off;\0"


#define CONFIG_EXTRA_ENV_SETTINGS \


Please take a note here, we enable channel 0 for solo, as 18 bit and enable fb1 set the device to LDB(LVDS).

  1. Kernel:

For Android 8.0: ~/var_o_800_100/imx-o8.0.0_1.0.0_ga/android_build/kernel_imx

For Android 7.1.2: ~/var_n_712_200/n_712_200_build/kernel_imx

diff --git a/arch/arm/boot/dts/imx6qdl-var-solocb-dt6cb-displays.dtsi b/arch/arm/boot/dts/imx6qdl-var-solocb-dt6cb-displays.dtsi

index 8876245..b329e9d 100644

--- a/arch/arm/boot/dts/imx6qdl-var-solocb-dt6cb-displays.dtsi

+++ b/arch/arm/boot/dts/imx6qdl-var-solocb-dt6cb-displays.dtsi

@@ -12,6 +12,14 @@

interface_pix_fmt = "RGB666";

};


+&mxcfb2 {

+ disp_dev = "ldb";

+ interface_pix_fmt = "RGB666";

+ default_bpp = <16>;

+ int_clk = <0>;

+ late_init = <0>;

+};

+

&i2c3 {

touch: ft5x06_ts@38 {

compatible = "edt,edt-ft5x06";

@@ -28,22 +36,21 @@


lvds-channel@0 {

fsl,data-mapping = "spwg";

- fsl,data-width = <24>;

- crtc = "ipu1-di0";

+ fsl,data-width = <18>;

status = "okay";


display-timings {

native-mode = <&timing0>;

timing0: hsd100pxn1 {

- clock-frequency = <35714000>;

+ clock-frequency = <32000000>;

hactive = <800>;

vactive = <480>;

- hback-porch = <24>;

- hfront-porch = <15>;

- vback-porch = <13>;

- vfront-porch = <20>;

- hsync-len = <20>;

- vsync-len = <13>;

+ hback-porch = <39>;

+ hfront-porch = <39>;

+ vback-porch = <29>;

+ vfront-porch = <13>;

+ hsync-len = <47>;

+ vsync-len = <2>;

};

};

};

@@ -51,7 +58,6 @@

lvds-channel@1 {

fsl,data-mapping = "spwg";

fsl,data-width = <18>;

- crtc = "ipu1-di1";

primary;

status = "okay";


  • Software Preparation for Dual Display (LVDS + HDMI):
  • Kernel:

For Android 8.0: ~/var_o_800_100/imx-o8.0.0_1.0.0_ga/android_build/kernel_imx

Compile the kernel with following changes in the device tree below.

http://variwiki.com/index.php?title=VAR-SOM-MX6_Android&release=RELEASE_O8.0.0_1.0.0_VAR-SOM-MX6#Build_boot.img


For Android 7.1.2: ~/var_n_712_200/n_712_200_build/kernel_imx

Compile the kernel with following changes in the device tree below

http://variwiki.com/index.php?title=VAR-SOM-MX6_Android&release=RELEASE_N7.1.2_2.0.0_VAR-SOM-MX6#Build_boot.img

Device Tree Changes :

diff --git a/arch/arm/boot/dts/imx6qdl-var-solocb-dt6cb-displays.dtsi b/arch/arm/boot/dts/imx6qdl-var-solocb-dt6cb-displays.dtsi

index 8876245..078138f 100644

--- a/arch/arm/boot/dts/imx6qdl-var-solocb-dt6cb-displays.dtsi

+++ b/arch/arm/boot/dts/imx6qdl-var-solocb-dt6cb-displays.dtsi

@@ -29,7 +29,7 @@

lvds-channel@0 {

fsl,data-mapping = "spwg";

fsl,data-width = <24>;

-crtc = "ipu1-di0";

+crtc = "ipu2-di0";

status = "okay";


display-timings {

@@ -51,7 +51,7 @@

lvds-channel@1 {

fsl,data-mapping = "spwg";

fsl,data-width = <18>;

-crtc = "ipu1-di1";

+crtc = "ipu2-di1";

primary;

status = "okay";


Install the boot image to respective platform and then at uboot prompt change the bootargs

U-Boot prompt commands :

=> setenv videoargs 'setenv bootargs ${bootargs} video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24 video=mxcfb1:dev=ldb consoleblank=0 video=mxcfb2:off video=mxcfb3:off;'

=> saveenv

=> reset

3) Android Framework changes (Optional) for Android 8.0 only:

If you wish to have activities to be launched on secondary panel


Add the line <feature name="android.software.activities_on_secondary_displays" /> to tablet_core_hardware.xml

This file is located at /system/etc/permissions/ on the Android

On the source side, the file is located at

For Android 8.0 : android_build/variscite/var_mx6/tablet_core_hardware.xml

This feature is required for setLaunchDisplayId(<display number>) to work.


4) Compile the image for your platform following

For Android 8.0 :

http://variwiki.com/index.php?title=VAR-SOM-MX6_Android&release=RELEASE_O8.0.0_1.0.0_VAR-SOM-MX6#Build_Android_Images

For Android 7.1.2 :

http://variwiki.com/index.php?title=VAR-SOM-MX6_Android&release=RELEASE_N7.1.2_2.0.0_VAR-SOM-MX6#Build_Android_Images


and program the image to VAR-SOM-SOLO/DUAL or DART-MX6


Testing : By default Android operates in clone mode, but if you wish to have two different content on two different panel; your Android application have to explicitly tell which display it wants to render the Surface. You can use the presentation mode.


Customer should be advised to use the presentation mode for testing / prototyping.

More information about presentation mode available here : https://developer.android.com/reference/android/app/Presentation


Reference :

<Your_Android_Build>/development/samples/ApiDemos->./src/com/example/android/apis/app/PresentationWithMediaRouterActivity.java is sample code.


If you wish to make apk for ApiDemos,

For Android 8.0:

$ cd ~/var_o_800_100/imx-o8.0.0_1.0.0_ga/android_build$ source build/envsetup.sh$ lunch var_mx6-engor$ lunch var_mx6-userdebug

$ cd development/samples/ApiDemos

mm

This should generate out/target/product/var_mx6/testcases/ApiDemos/ApiDemos.apk copy apk to your present directory from which you can install on the platform

Connect OTG and use adb to install using below command.

$adb install ApiDemos.apk


For Android 7.1.2:

$ cd ~/var_n_712_200/n_712_200_build$ source build/envsetup.sh$ lunch var_mx6-engor$ lunch var_mx6-user

$ cd development/samples/ApiDemos

mm

This will generate apk on out/target/product/var_mx6/data/app/ApiDemos/ApiDemos.apk path which you can install on the platform. Copy apk to your present directory from which you can install on the platform.

$adb install ApiDemos.apk


Note : For LVDS + HDMI case , at command prompt run below commands

# echo 0 > /sys/class/graphics/fb2/blank


By default Android will clone the primary display to secondary unless you specify in the application layer for which display to use using presentation mode.


Your screen should look like this after installation

[[Image:]]


Click on API Demos


[[Image:]]


Click on App should give you screen as below

[[Image:]]


Click on Activity Should give you screen as below

[[Image:]]


Click on Presentation with Media Router


Once you do that you should see the output on 2nd panel different than the first panel like below


[[Image:]]

Here in left side is secondary panel (LVDS0) and right side which is primary panel (LVDS1).


Note :

  • In case of LVDS + HDMI the HDMI is your primary panel so you will see spinning cubes on the LVDS and Android main UI on HDMI monitor.
Retrieved from "https://variwiki.com/index.php?title=Dual_Display&oldid=10217"
Latest Modules
Support
Variscite Support Center
Contact Support
Product Longevity
Product Compliance Policy
Blog
Variscite Training
Variscite Website
This page was last edited on 13 September 2018, at 18:56.

© 2024 Variscite. All rights reserved