MX8 Display: Difference between revisions
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VAR-SOM-MX8 supports DP, HDMI and LVDS displays. DP and HDMI require Variscite extension boards VAR-EXT-DP and VAR-EXT-HDMI.<br> | VAR-SOM-MX8 supports DP, HDMI and LVDS displays. DP and HDMI require Variscite extension boards VAR-EXT-DP and VAR-EXT-HDMI.<br> | ||
Selecting display configuration is a matter of selecting an appropriate DTB file.<br> | Selecting display configuration is a matter of selecting an appropriate DTB file.<br> | ||
File /boot/fsl-imx8qm-var-som.dtb is a symbolic link to the active DTB file. By default LVDS | File /boot/fsl-imx8qm-var-som.dtb is a symbolic link to the active DTB file. By default it points to LVDS DTB.<br> | ||
To select HDMI display, run the following commands: | |||
# cd /boot | # cd /boot | ||
# ln -fs fsl-imx8qm-var-som-hdmi.dtb fsl-imx8qm-var-som.dtb | # ln -fs fsl-imx8qm-var-som-hdmi.dtb fsl-imx8qm-var-som.dtb | ||
To select DP display, run the following commands: | |||
# cd /boot | |||
# ln -fs fsl-imx8qm-var-som-dp.dtb fsl-imx8qm-var-som.dtb | |||
The change will be effective after reboot.<br> | The change will be effective after reboot.<br> | ||
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HDMI and DP displays require appropriate firmware to be loaded by u-boot. The firmware files are installed under /boot.<br> | HDMI and DP displays require appropriate firmware to be loaded by u-boot. The firmware files are installed under /boot.<br> | ||
The HDMI display firmware blob is hdmitxfw.bin, the DP firmware blob is dpfw.bin. U-Boot environment variable hdp_file selects the blob.<br> | The HDMI display firmware blob is hdmitxfw.bin, the DP firmware blob is dpfw.bin. U-Boot environment variable hdp_file selects the blob.<br> | ||
By default HDMI firmware is loaded. To switch to DP firmware run the following command: | By default HDMI firmware is being loaded. To switch to DP firmware, run the following command: | ||
# fw_setenv hdp_file dpfw.bin | # fw_setenv hdp_file dpfw.bin | ||
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The change will be effective after reboot.<br> | The change will be effective after reboot.<br> | ||
{{Note|Both firmware blob and DTB file should be set before rebooting the system, otherwise the boot process will | {{Note|Both firmware blob and DTB file should be set before rebooting the system, otherwise the boot process will get stuck.}} | ||
= Setting HDMI and DP resolution = | = Setting HDMI and DP resolution = | ||
By default the maximum resolution supported by HDMI/DP display is used.<br> | By default the maximum resolution supported by HDMI/DP display is being used.<br> | ||
To check the current resolution, run fbset command. | To check the current resolution, run fbset command. | ||
<pre> | <pre> | ||
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= LVDS = | = LVDS = | ||
{{#var:HARDWARE_NAME}} supports one dual-channel LVDS interface.<br> | {{#var:HARDWARE_NAME}} supports one dual-channel LVDS interface.<br> | ||
{{#var:HARDWARE_NAME}} evaluation kit comes with two LVDS connectors, one connector per LVDS channel.<br> | |||
By default Variscite panel is attached to LVDS#A connector.<br> | By default Variscite panel is attached to LVDS#A connector.<br> | ||
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To support different LVDS panel, several modifications may be required. | To support different LVDS panel, several modifications may be required. | ||
The following code configures LVDS panel in arch/arm64/boot/dts/freescale/{{#ifeq: {{#var:HARDWARE_NAME}}|VAR-SOM-MX8X|fsl-imx8qxp-var-som-common.dtsi|fsl-imx8qm-var-som-lvds.dtsi}} under kernel source tree | The following code configures LVDS panel in arch/arm64/boot/dts/freescale/{{#ifeq: {{#var:HARDWARE_NAME}}|VAR-SOM-MX8X|fsl-imx8qxp-var-som-common.dtsi|fsl-imx8qm-var-som-lvds.dtsi}} under kernel source tree: | ||
{{#ifeq: {{#var:HARDWARE_NAME}}|VAR-SOM-MX8X| | {{#ifeq: {{#var:HARDWARE_NAME}}|VAR-SOM-MX8X| |
Revision as of 14:23, 15 September 2019
LVDS
VAR-SOM-MX8X supports one dual-channel LVDS interface.
VAR-SOM-MX8X evaluation kit comes with two LVDS connectors, one connector per LVDS channel.
By default Variscite panel is attached to LVDS#A connector.
Adding custom LVDS panel
VAR-SOM-MX8X evaluation kit comes with 800x480 LVDS panel.
VAR-SOM-MX8X DTS file was created with this panel in mind.
To support different LVDS panel, several modifications may be required.
The following code configures LVDS panel in arch/arm64/boot/dts/freescale/fsl-imx8qxp-var-som-common.dtsi under kernel source tree:
&ldb1_phy { status = "ok"; }; &ldb1 { status = "ok"; lvds-channel@0 { fsl,data-mapping = "jeida"; fsl,data-width = <24>; status = "ok"; display-timings { lvds { clock-frequency = <29232000>; hactive = <800>; vactive = <480>; hback-porch = <40>; hfront-porch = <40>; vback-porch = <29>; vfront-porch = <13>; hsync-len = <48>; vsync-len = <3>; hsync-active = <0>; vsync-active = <0>; de-active = <1>; pixelclk-active = <0>; }; }; }; };
You may need to modify "fsl,data-mapping", "fsl,data-width" and "display-timings" properties to match your panel specification.
For more information see Documentation/devicetree/bindings/display/imx/ldb.txt in the kernel source tree.
Setting Weston Desktop Resolution
The default Weston uses maximum resolution supported by display.
To modify Weston resolution, edit /etc/xdg/weston/weston.ini and set size parameter in shell section.
For example, to set 1080P resolution
[shell] size=3840x2160
For new settings to take effect restart weston by running
# systemctl restart weston