Hi All
The red colour on my LCD is little off, it does not exactly looks like perfect red. So i want to calibrate this LCD. And i am looking for the suggestion to do that:
here is gamma correction steps, i already tried and did not get the good result
Gamma correction on i.MX6
ipu-examples release notes - v0.1
ipu-examples/framebuffer_ex1.c at master · rogeriorps/ipu-examples · GitHub
Tried above gamma correction sample code but LCD calibration become more bad.
here is my platform and setting for LVDS interface :[ Android 4.4 kernel 3.10 ]
LCD panel uses (HX8282 -Source driver / HX8696 -Gate Driver) ---SPI interface is not out from the Panel for control so i can not set the panel registers.
====(drivers/video/mxc/mxc_lcdif.c)===================================
static struct fb_videomode lcdif_modedb[] = {
{
/* lcd 1024x600 @ 60 Hz , pixel clk @ 66MHz */
"HiMAX-WSVGA", 60, 1024, 600, 25000 , 155, 160, 8, 23, 4, 4,
FB_SYNC_CLK_LAT_FALL,
FB_VMODE_NONINTERLACED,
0,},
};
===( DTS file ) ===========:
mxcfb1: fb@0 {
compatible = "fsl,mxc_sdc_fb";
disp_dev = "ldb";
interface_pix_fmt = "RGB24";
default_bpp = <24>;/*<24>;*/
int_clk = <0>;
late_init = <0>;
status = "okay";
};
================================================================
Questions :
1) I used the ipu example code for gamma correction, where Gout array is :
int gout[16] = {0,2,4,8,16,32,64,96,128,160,192,224,255,255,255,255}; this setting do not have any impact on my LCD color, is there any other gout value for my processor imx6dl , which i need to use or How will i calculate these value , any suggestion ?
2) Reference manual section: 38.4.9.6 Gamma correction says" Required gamma correction slope for a specific panel/display should be provided by the display manufacturer " , can you point me, what will be the value i will be suing from gamma slope in the sample code ?
3) Regarding Data format, My LCD support RGB stripe(LCD document does not provide good details about this), And "RGB24" is working for me with reasonable result. Android HAL is using HAL_PIXEL_FORMAT_RGB_565 . is there anything i need to look from this perspective, In terms of IPU Color space conversion ?
4) Any other pointer or reference for LCD panel calibration ?
Thanks
Robin Singh
