User`s guide

Supporting the i.MX53 Reference Board DISP0 LCD
i.MX53 System Development User’s Guide, Rev. 1
18-8 Freescale Semiconductor
For example, the kernel command for an XGA LVDS connected to LVDS0 using DI1 as the primary
display interface is as follows:
video=mxcdi0fb:RGB24,LDB-XGA di1_primary
18.3.3 Modifying the Bits per Pixel Setting
The default bits per pixel setting is 16 bits. To change the default value to another depth, modify the
relevant lines in the mxc_ipuv3_fb.c file located at
<ltib dir>/rpm/BUILD/linux/drivers/video/mxc/mxc_ipuv3_fb.c
Example 18-4. Changing the Frame Buffer to 32 bpp
The following example code shows how to change the frame buffer from 16 bpp to 32 bpp.
static int mxcfb_probe(struct platform_device *pdev)
{
...
if (!mxcfbi->default_bpp)
mxcfbi->default_bpp = 16;
// Change Default BPP to 32 bpp
printk(KERN_INFO "mxcfb_probe() - default_bpp = 32\r\n");
mxcfbi->default_bpp = 32;
...
return ret;
}
Check the frame buffer bpp and other settings in the /sys/class folder. The output should look like the
following:
root@freescale ~$ cd /sys/class/graphics/fb0/
root@freescale /sys/devices/platform/mxc_sdc_fb.1/graphics/fb0$ ls
bits_per_pixel device pan subsystem
blank fsl_disp_property power uevent
console mode rotate virtual_size
cursor modes state
dev name stride
root@freescale /sys/devices/platform/mxc_sdc_fb.1/graphics/fb0$ cat bits_per_pixel
32
Note that the final line shows the bits per pixel to be 32, reflecting our change from the default of 16 bpp.
18.3.4 Modifying Display Timing for CLAA057VA01CT Using Kernel
Parameters
By using the video and di1_primary kernel parameters, the frame buffer driver is able to change all timing
and interface aspect ratios. Timing is calculated using the VESA standard.