framebuffer

强王 — Wed, 15 Jul 2015 09:59:18 GMT

现在对fb这块还是不熟悉，问几个问题

1：一块屏幕对应几个fb是由屏幕决定的还是由驱动决定的？

2：假如是驱动决定，目前freescale的是2个fb，可不可以初始化一个屏幕为3个fb

Re: framebuffer

Bio_TICFSL — Fri, 17 Jul 2015 13:28:40 GMT

Hi Qiang Wang,

The screen resolution should be set in your EGL code. If you like to get two outpout fb with the same context, you have to use multiple-buffer rendering, set the environment variable FB_MULTI_BUFFER to an unsigned integer value, which indicates the number of buffers required. Recommended values: 2 or 3 The FB_MULTI_BUFFER variable can be set to any positive integer value.

If set to 1, the multiple buffer function is not enabled.

If set to 2 or 3, the driver will run as users expect.

If set to a value more than 3, the driver will use 3 as the buffer count.

To create a window with its size different from the display size, use the environment variable FB_IGNORE_DISPLAY_SIZE. Example usage syntax: export FB_IGNORE_DISPLAY_SIZE=1 To let the driver use multiple buffers to do swap work, use the environment variable FB_MULTI_BUFFER. Example usage syntax: export FB_MULTI_BUFFER=2

To specify the display device, use the environment variable FB_FRAMEBUFFER_n, where n = any positive integer. Example usage syntax: export FB_FRAMEBUFFER_0=/dev/fb0 export FB_FRAMEBUFFER_1=/dev/fb1 export FB_FRAMEBUFFER_2=/dev/fb2 export FB_FRAMEBUFFER_3=/dev/fb3

Hope this helps

topic Re: framebuffer in i.MX Processors

framebuffer

Re: framebuffer