I have an Apalis IMX6q, on an Ixora carier and want to attach an LVDS display 1920x1200 that use 2 channels LVDS.
I configured DTS in this way:
diff --git a/arch/arm/boot/dts/imx6qdl-apalis.dtsi b/arch/arm/boot/dts/imx6qdl-apalis.dtsi
index cebd78f2a34e..78b8c3bc83c2 100644
--- a/arch/arm/boot/dts/imx6qdl-apalis.dtsi
+++ b/arch/arm/boot/dts/imx6qdl-apalis.dtsi
@@ -92,10 +92,10 @@
mxcfb1: fb@0 {
compatible = "fsl,mxc_sdc_fb";
disp_dev = "ldb";
- interface_pix_fmt = "RGB666";
- default_bpp = <16>;
+ interface_pix_fmt = "LVDS666";
+ default_bpp = <32>;
int_clk = <0>;
status = "disabled";
};
@@ -523,19 +523,34 @@
&ldb {
status = "okay";
-// split-mode;
+ split-mode;
// dual-mode;
lvds-channel@0 {
reg = <0>;
fsl,data-mapping = "spwg"; /* "jeida"; */
- fsl,data-width = <18>;
+ fsl,data-width = <24>;
crtc = "ipu2-di1";
primary;
status = "okay";
display-timings {
- native-mode = <&timing_xga>;
+ native-mode = <&timing_wuxga>;
+ timing_wuxga: 1920x1200M {
+ clock-frequency = <149992500>;
+ hactive = <1920>;
+ hback-porch = <20>;
+ hfront-porch = <100>;
+ hsync-len = <18>;
+ hsync-active = <0>;
+ vactive = <1200>;
+ vback-porch = <4>;
+ vfront-porch = <6>;
+ vsync-len = <2>;
+ vsync-active = <0>;
+ de-active = <1>;
+ pixelclk-active = <0>;
+ };
/* LDB-AM-800600LTNQW-A0H */
timing_svga: 800x600 {
clock-frequency = <55000000>;
And if I start the kernel with:
setenv vidargs 'video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off fbmem=32M'
I get bad image:
[upload|gfL8fa19pZxIDsb0JXA85eE+JV8=]
But the time parameters are configured correctly:
[ 24.102946] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 18,100,20 v_sync,l,u: 2,6,4 pixclock=149992000 Hz
root@apalis-imx6:~# [ 24.301451] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 18,100,20 v_sync,l,u: 2,6,4 pixclock=149992000 Hz
[ 24.399321] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 18,100,20 v_sync,l,u: 2,6,4 pixclock=149992000 Hz
[ 24.499760] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 18,100,20 v_sync,l,u: 2,6,4 pixclock=149992000 Hz
root@apalis-imx6:~# [ 31.827127] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 18,100,20 v_sync,l,u: 2,6,4 pixclock=149992000 Hz
root@apalis-imx6:~#
root@apalis-imx6:~# [ 36.313123] usb_otg_vbus: disabling
fbset
mode "1920x1200-60"
# D: 149.993 MHz, H: 72.883 kHz, V: 60.134 Hz
geometry 1920 1200 1920 1200 32
timings 6667 20 100 4 6 18 2
rgba 8/16,8/8,8/0,8/24
endmode
Noting that the right side seems stretched, like the secondary channel is not configured or configured with a bad parameters
Now if I start the kernel with this parameters
setenv vidargs 'video=mxcfb0:dev=ldb,1920x1200M@60,if=LVDS666 video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off fbmem=32M'
It will seems better (there are some flickerig and bad timing parameters configured, the clock is very high 194Mhz (why?!?!))
[upload|+MDKBXGOiep+Lns86XOP9qaMNsU=]
[ 13.098593] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 200,136,336 v_sync,l,u: 6,3,36 pixclock=193274000 Hz
[ 13.289203] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 200,136,336 v_sync,l,u: 6,3,36 pixclock=193274000 Hz
[ 13.366268] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 200,136,336 v_sync,l,u: 6,3,36 pixclock=193274000 Hz
[ 13.436650] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 200,136,336 v_sync,l,u: 6,3,36 pixclock=193274000 Hz
[ 13.448381] IPv6: ADDRCONF(NETDEV_UP): usb0: link is not ready
[ 14.042231] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 200,lock=193274000 Hz
[ 36.313195] usb_otg_vbus: disabling
root@apalis-imx6:~#
root@apalis-imx6:~#
root@apalis-imx6:~# fbset
mode "1920x1200-60"
# D: 193.274 MHz, H: 74.566 kHz, V: 59.892 Hz
geometry 1920 1200 1920 1200 32
timings 5174 336 136 36 3 200 6
vsync high
rgba 8/16,8/8,8/0,8/24
The parameters are not what I configured in DTS, and if I set them with fbset
root@apalis-imx6:~# fbset -t 6667 20 100 4 6 18 2 -vsync false -g 1920 1200 1920 1200 32 -s
[ 225.206666] mxc_sdc_fb fb@0: 1920x1200 h_sync,r,l: 18,100,20 v_sync,l,u: 2,6,4 pixclock=149992000 Hz
mode "1920x1200-60"
# D: 149.993 MHz, H: 72.883 kHz, V: 60.134 Hz
geometry 1920 1200 1920 1200 32
timings 6667 20 100 4 6 18 2
rgba 8/16,8/8,8/0,8/24
endmode
Now everything seems better, the timing and image seems very good:
[upload|0Tfk1PkdHzn79JZNZufMz0Taugs=]
Now:
- What’s the difference from video:dev=ldb,1920x1200M,if=LVDS666 and my DTS mxcfb1: fb@0 configuration? I suppose that the if=LVDS666 is not the same as interface_pix_fmt = “LVDS666”;
in my DTS!? - The M in mode 1920x1200M will do some automatic calculation of timing, but it is wrong, but probably do some other thing that my DTS not configure
- How I can setting all in the DTS?
- … Or how I can sett all parameters (timing and pixel clock and vsync=false) in the vidargs at startup?
