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shafy.s , 02-15-2017, 10:16 AM

Hi,

We are trying to interface a 5" hdmi LCD (800x480) with the openrex quad board . (http://www.waveshare.com/5inch-hdmi-lcd.htm).
Openrex is running the yocto kernel and rootfs. But the LCD is not showing the xterm properly. It is showing only partial.

We tried to change the hdmi resolution as in http://www.imx6rex.com/open-rex/soft...ipherals/#hdmi
It seems like 800x480 resolution is not supported in the hdmi driver, so we tried editing the kernel driver file as follows

The struct fb_videomode vga_mode in 'mxc_hdmi.c'
The following values were used static const struct fb_videomode vga_mode = {
/* 800x480 @ 60 Hz, 31.5 kHz hsync */
NULL, 60, 800, 480, 29850, 89, 164, 23, 10, 10, 10, 0,
FB_VMODE_INTERLACED | FB_VMODE_ASPECT_4_3, 0,
};


And in and fb_videomode mxc_cea_mode in mxc_edid.c.

[1] = {
NULL, 60, 800, 480, 29850, 89, 164, 23, 10, 10, 10, 0,
FB_VMODE_INTERLACED | FB_VMODE_ASPECT_4_3, 0
},


Can anyone advise anything else need to be edited in the driver ?

Thanks
Shafy

robertferanec , 02-15-2017, 05:50 PM

I do not really know you may need to google for it e.g. "imx6 hdmi 800x480" ... that is what I would try.

ranaya , 04-24-2017, 10:35 PM

Hi, are you using X11 graphical environment ? If yes, try loading a new xrandr mode after setting your display :

export DISPLAY=:0.0 (to relavent frame buffer)
xrandr --newmode "1440x480i-60" 27 1440 1475 1604 1714 480 481 483 525 interlace -hsync -vsync
xrandr --addmode "DISP3 BG" 1440x480i-60
xrandr --output "DISP3 BG" --mode 1440x480i-60

This DISP3 BG should be the BG overlay of hdmi frame buffer. I used above example to set interlace video modes to lcd interface (24 bit parallel RGB) through its frame buffer ! In similar fashion, this can be done to hdmi as well.