On Mon, Jun 13, 2016 at 5:41 PM, vinoth eswaran evinoth1206@gmail.com wrote:
Hello Mr.Bin, Hello Mr.George McCollister,
I am working on an embedded project to optimize Linux boot up time. I have a camera application, which I need to run as fast as possible after powering up the board.
For this currently I am analyzing how can I optimize the U-boot. As of now, u-boot takes around 3 to 4 seconds and most of the time is spent, around 2 secs in initializing the VESA display.
I have analyzed the sequence of VESA initialization flow and I have identified that realmode_call under the function bios_run_on_x86() takes more time -- around 1.7 Sec,
realmode_call(addr + 0x0003, num_dev, 0xffff, 0x0000, 0xffff, 0x0, 0x0);Do you have any idea why this is happening?
I tried removing the VIDEO configuration from u-boot, though the boot up is fast , the i915 driver from Linux is reporting an error -- 'i915 0000:00:02.0: Invalid ROM contents'
Can you point out which file in the kernel source that reports this? I cannot find such message in latest kernel source tree.
I understand that the Linux kernel expects the underlying boot loader to setup some initialization which is missing in this case.
My understanding is that if we have native graphics driver in the kernel, then the bootloader does not need initialize the graphics hardware.
Do you know any methods by which I can speed up the video driver initialization phase in u-boot. Please note that I don't need video support during u-boot phase,I am not going to use any splash images.
Regards, Bin