Is there some existing way to do early printk type output to a framebuffer that has been set up by the bootloader? early printk is before any device drivers are loaded. If not, what would it take to create a way to do this? Something along the lines of build in the fbdev library and give it an address plus x/y layout of the buffer. Assume that everything else is set up and anything written to the buffer will appear on the display. Then hook into where the kernel does early printk on uarts and add in support for this buffer. The core fbdev library implements scrolling and graphical characters. I'm only looking to address early boot messages so that if the kernel fails to boot before it can get to a real video driver, the output is still visible. Note that you get this early output right now, but it is buffered by the kernel until the console driver is loaded, then it gets dumped. If you fail before that console driver loads you see nothing. The idea is to make the output that gets lost visible. To communicate this you need the existing fb mode line on the kernel command line (to get x/y layout) plus the framebuffer address. Or this info can come via the DT. No intention to keep this display working once real display drivers get loaded. So no touching clocks, regulators, display modes, etc.... -- Jon Smirl jonsmirl@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
