Adjust Diplay Offset

Hello,

we have a 7inch TFT Liquid Crystal Display module with LVDS interface (G070Y2-L01 / Data Module AG) and use the Apalis_iMX6_LinuxImage-qtV2.6_20160615 Image build with “bitbake -k angstrom-qt-x11-image”.
In U-Boot we use imx6q-apalis-ixora.dtb device tree and change the vidargs Var :

vidargs=mxc_hdmi.only_cea=1 video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24 video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off fbmem=32M
to
vidargs=video=mxcfb0:dev=ldb
After that we boot. Unfortunately the display has an offset (shift to left and bottom ).

How can we fix this ?

best regards

Lars

Hi Lars

You likely will have to set your display timings in the device tree, e.g. here:
http://git.toradex.com/cgit/linux-toradex.git/tree/arch/arm/boot/dts/imx6qdl-apalis.dtsi?h=toradex_imx_3.14.52_1.1.0_ga&id=7c83cef87116c0b2aaaf867f406831643306d3d1#n1017

From the datasheet it looks like your display does not like Hsync, Vsync signals at all. For this we do not have a real solution. This discussion might be helpfull which allows you to set the Hsync to 0.

Max

Hi Max,
thanks for your response. The problem is now fixed. I add a new “display-timings” entry to my device tree and adjust the timings/resolution. For the G070Y2-L01 i take this setup:

timing_wvga: 860x480 {
	clock-frequency = <29500000>;
	hactive = <800>;
	vactive = <480>;
	hback-porch = <96>;
	hfront-porch = <16>;
	vback-porch = <12>;
	vfront-porch = <4>;
	hsync-len = <80>;
	vsync-ten = <4>;
	hsync-active = <0>;
	vsync-active = <0>;
	pixelclk-active = <0>;
	};

" From the datasheet it looks like your display does not like Hsync, Vsync signals at all. For this we do not have a real solution. This discussion might be helpful which allows you to set the Hsync to 0. "

I try : hsync-acttve = <0>; vsync-active = <0>; & hsync-active = <1>; vsync-active = <1>; . Both worked.

One additional Question:
How can i select/switch to other display-timings from the dtb ?( e.g. timing_xga, timing_wxga )
When i run fbset -i on target i only see the mode correspond to my added display-timing. Can i select them from BL via vidargs Var ?

Best regards

Lars