How to configure independent LVDS displays? I have dual mode working

[mstevens]

About 6 months ago, I successfully brought up two Industrial 800x480 LVDS displays running in dual mode (my patch to the dts file is attached).

What changes do I need to make to make the displays independent? 

Simply changing the mode is not enough.  My displays show that I have something clocked wrong (they do the funky wave of black).

My timing is correct for both of them for dual.  In looking at ldb.c I see that dual mode runs with a different divider than other modes.  (in certain modes it is divide by 3.5).

First what the correct mode so I can have two independent display?  I think split.

Second do I double or halve the clock?  I've tried both for split mode, no joy

Is there another setting I need to change? 

I've tried making fb2 and fb3 matching fb1.

mxcfb1: fb@0 {
compatible = "fsl,mxc_sdc_fb";
disp_dev = "ldb";
mode_str ="LDB-XGA";
interface_pix_fmt = "RGB24";
default_bpp = <24>;
int_clk = <0>;
late_init = <0>;
status = "disabled";
};

Any help would be appreciated.  I've struggled with this for a while.  

Original Attachment has been moved to: 0004-Display.patch.zip

[mstevens · Accepted solution]

The answer is separate-mode was all I was missing (thank Igor)

Also note that my second display ended up on fb2.  

ldb {
status = "okay";
separate-mode;  //MSS: THIS IS THE KEY!
lvds-channel@0 {
fsl,data-mapping = "jeida";
fsl,data-width = <24>;
primary;  //MSS: Make sure you have this
status = "okay";

display-timings {
native-mode = <&timing0>;
timing0: hsd100pxn1 {
clock-frequency = <33260000>;
hfront-porch = <40>;
hactive = <800>;
hback-porch = <88>;
hsync-len = <128>;

vactive = <480>;
vfront-porch = <10>;
vback-porch = <33>;
vsync-len = <2>;
};
};
};

lvds-channel@1 {
fsl,data-mapping = "jeida";
fsl,data-width = <24>;
status = "okay";
crtc = "ipu1-di1"; //MSS Make sure you have this

display-timings {
native-mode = <&timing1>;
timing1: hsd100pxn1 {
clock-frequency = <33260000>;
hfront-porch = <40>;
hactive = <800>;
hback-porch = <88>;
hsync-len = <128>;

vactive = <480>;
vfront-porch = <10>;
vback-porch = <33>;
vsync-len = <2>;
};
};
};
};

[igorpadykov]

Hi Michael

split mode is used for one display with high resolution,

for two independent displays separate mode should be used.

Please refer to Table 39-5. Channel Mapping i.MX6DQ Reference Manual

http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6DQRM.pdf

and attached Release Notes from older kernel Table 6. Kernel Boot Parameters

"ldb" parameter, it provides some better description.

Best regards
igor
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[mstevens]

Igor,

I did not get the release notes.  The Channel Mapping is extremely low level and I hope the driver will handle it.