Hi, I use LVDS with http://www.yslcd.com.tw/docs/product/B140XTT01.0.pdf. I had a kernel 3.14.28 and u-boot 2015-07-15122. I have a problem with screen colors, when I entered to u-boot comand line, screen show correct colors, but when I boot the linux, the colors are not correct. I attached the pictures.
Thank for o your replay.
I used the formula from your previous post, but when i restart, bootloader had crashed. I changed the hannstar7 settings to my screen settings. Below I attach the equtions which I used:
The maximum clock frequency = (1366+B)*(768+A)*60 < 80MHz
xres = horizontal valid = 1366 = hactive
left margin = horizontal period - horizontal valid = 1456 - 1366 = 90 = hback-porch
right margin = 0 = hfront-porch
hsync_len = 0 = hsync-len
yres = vertical valid = 768 = vactive
upper margin = vertical period - vertical valid = 824 - 768 = 56 = vback-porch
lower margin = 0 = vfront-porch
vsync_len = 0 = vsync-len
Now I have a black screen. Do you have some idea, what it's wrong?
I attached the screen-shots:
- list of screen settings in fbpanel function
- u-boot printenv
- booting u-boot
- booting a linux
Resolution in the new kernel 3.14.28 is changing at u-boot via fbpanel function. I added my resolutions to this function. I have a some idea what should be wrong.
I attached the screenshot from include file of devicetree (imx6qdl-sabresd.dtsi). Pleas pay attention to 'ldb' and 'lcd'. The 'ldb' had a interface_pix_fmt=RGB666 and default_bpp=16, but 'lcd' had a interface_pix_fmt=RGB565 and default_bpp=16. I think, the 'ldb' work with 16 RGB bits like 'lcd' standard. What do you about it? Tommorow i try this and attached the linux and u-boot full log.
Actually we (Boundary Devices) provide fb_panel command in U-Boot in order to list the different displays we support and that we can set dynamically in the device tree.
So if your display is not part of the list, you need to either add it to U-Boot source code or define a fb_lvds variable which defines your display timings:
=> setenv fb_lvds <name>:<interface>:<clock-frequency>,<hactive>,<vactive>,<hback-porch>,<hfront-porch>,<vback-porch>,<vfront-porch>,<hsync-len>,<vsync-len>
Otherwise you can change it yourself in the device tree but know that:
seems this lcd with resolution 1366 x768 is not supported in bsp, so
appropriate kernel boot parameter should be added. One can look at
Can you please copy the full serial output log to pastebin so we can see what is recognized by U-Boot and later configured in the kernel?