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HDMI+LVDS0 Mirror IMX6 Solo

Question asked by Luis Roberto Togo Peraza on Nov 5, 2016
Latest reply on Jan 25, 2018 by Matthias Wallnöfer



I'm having a real bad time trying to setup HDMI+LVDS0 display mirror in IMX6 Solo.


I have gone through several posts regarding this issue but non of them work.


Here my setup:


1) I'm using Wandboard Solo with a custom carrier board

2) Yocto Dizzy (Linux 3.10.17)

3) I have a 1024x600 LVDS screen connected to LVDS0

4) I have a remote "monitor" 1024x600 on HDMI


This is my configuration on the dtb:


mxcfb1: fb@0 {
compatible = "fsl,mxc_sdc_fb";
disp_dev = "hdmi";
interface_pix_fmt = "RGB24";
mode_str ="1280x720M@60";
default_bpp = <24>;
int_clk = <0>;
late_init = <0>;
status = "disabled";


mxcfb2: fb@1 {
compatible = "fsl,mxc_sdc_fb";
disp_dev = "ldb";
interface_pix_fmt = "RGB24"; /*TOGO CHANGED INTERFACE TO RGB888*/
default_bpp = <24>; /*TOGO CHANGED TO 24BITS*/
int_clk = <0>;
late_init = <0>;
status = "disabled";



&hdmi_core {
ipu_id = <0>;
disp_id = <0>;
status = "okay";


&ldb {
ipu_id = <0>;
disp_id = <1>;
ext_ref = <1>;
mode = "sin0";
sec_ipu_id = <1>;
sec_disp_id = <1>;
status = "okay";


Here my bootargs:

setenv bootargs console=ttymxc0,115200 root=/dev/mmcblk0p2 rootwait rw video=mxcfb0:dev=ldb,LDB-WSVGA,if=RGB888 video=mxcfb1:dev=hdmi,1280x720M@60,if=RGB24


Now this is my situation:

I have a total of 6 boards, 3 of them perform the mirror perfectly using the configurations above, the other 3 just show LVDS0 and HDMI is OFF.


I have swapped boards and so on and the failure always follows the "cpu", for instance if I take the sdcard from a "good" CPU and place it in a "bad" CPU the issue is still on the bad CPU. If I swap carriers between a bad CPU and a good CPU then again the failure follows the CPU.


I know HDMI is working on the "bad" CPUs because when I enter to uboot I can see the "Wandboard" logo on the HDMI monitor.


Could it be possible that the "bad" CPUs are somehow damaged? But could it be that only the screen mirror is damaged? All other functions of the board are working 100%


I checked the boot-up log and dmesg and didn't find any significant difference.


I would really appreciate any input you might have, this issue is driving really me crazy.


UPDATE 1: today I switched ON a "bad" board and I was able to see TUX on the HDMI monitor, later on when the application started TUX is gone and I have no longer HDMI video. I switched OFF/ON the board and again HDMI is not shown any longer... This tells me again HDMI is fine on the PCB and seems to be an initialization problem.


UPDATE 2: attached the DMESG of a "bad " cpu, in general it looks the same as a "good" cpu; I notice that LVDS0  is changed from DI1 to DI0 by the LDB driver which theoretically will conflict with HDMI; but the funny thing is that the same setup and same configuration works OK on the "good" CPUs, thus this seems not to be the problem.




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