24bit LVDS display looks like wrong color depth on custom imx6q

[dougcrawford]

I have a 24bit LVDS display that I am running on a custom imx6q board.  The images look like they are being displayed at the wrong color depth and have some odd horizontal scan line artifacts.

I have modified drivers/video/mxc/ldb.c to add a new entry for my display:

static struct fb_videomode ldb_modedb[] = {

  {

  "LG-WVGA", 60, 800, 480, 30066, /*DE mode only. horizontal blanking 256 (85 + 85 + 86), vert blanking 45 (15 + 15 + 15) */

  85, 85,

  15, 15,

  86, 15,

  0,

  FB_VMODE_NONINTERLACED,

  FB_MODE_IS_DETAILED,},

I also modified my kernel board file to add a matching entry and made sure to specify IPU_PIX_FMT_RGB24

static struct ipuv3_fb_platform_data qmx6_fb_data[] = {

  { /*fb0*/

	.disp_dev = "ldb",
	.interface_pix_fmt = IPU_PIX_FMT_RGB24,
	.mode_str = "LG-WVGA",
	.default_bpp = 32,
	.int_clk = false,
	.late_init = false,
	}, {
	.disp_dev = "hdmi",
	.interface_pix_fmt = IPU_PIX_FMT_RGB24,
	.mode_str = "1920x1080M@60",
	.default_bpp = 32,
	.int_clk = false,
	.late_init = false,
	}, {
	.disp_dev = "ldb",
	.interface_pix_fmt = IPU_PIX_FMT_RGB24,
	.mode_str = "LG-WVGA",
	.default_bpp = 32,
	.int_clk = false,
	.late_init = false,
	},

};

Is there something else I need to setup in u-boot in order to get a 24bit LVDS panel working?  Could this be more related to the custom cable I have connecting the display to the board?

[sunyd]

hi,Doug Crawford:

my problem is almost like you ,and has your problem been solved?

thanks

[Milco]

Hi Doug,

you can try to set the correct display setup in u-boot bootargs by adding: video=mxcfb0:dev=ldb,LG-WVGA,if=RGB24 ldb=sin0

However, by viewing the posted image, there may be a problem of clock polarity, you can try change your display setup with:

static struct fb_videomode ldb_modedb[] = {

  {

  "LG-WVGA", 60, 800, 480, 30066, /*DE mode only. horizontal blanking 256 (85 + 85 + 86), vert blanking 45 (15 + 15 + 15) */

  85, 85,

  15, 15,

  86, 15,

  FB_SYNC_CLK_LAT_FALL,

  FB_VMODE_NONINTERLACED,

  FB_MODE_IS_DETAILED,},

About the custom cable,the successful implementation of the cable is fundamental.

[turkersezgin]

Hello everyone,

I have a toucshcreen display. It is DE mode only.

I dont have good view on the display. I only made some modifications at my_board.dtsi file.

Also, should I do something at ldb.c file? Because it is connected to board with LVDS connector.

Should I write my display parameters in ldb.c file?

Bootargs parameter is ldb=SVGA. So I have to write my display's parameters in SVGA? Right?

Thanks.

Have a nice day.