Hello Stephan
On 11-08-14 18:53, Stephen Warren wrote:
On 08/10/2014 10:53 AM, Jeroen Hofstee wrote:
Hello Stephan,
On 10-08-14 05:11, Stephen Warren wrote:
The entire point of this series is to prevent distros from having to
install bootloader-specific boot configuration files.
>
I fail to see why this is something to pursue. Since the distro knows
the boot path, why should u-boot be polling all possible options?
This patch series allows U-Boot to find the OS and boot it. U-Boot is
searching for some kind of boot configuration file.
This part of the process is the same as the BIOS searching all known
possible boot devices for a partition marked bootable, and with a
valid MBR. Or, it's the same as UEFI searching all possible boot
devices for whatever config file or boot binary is mandated by UEFI.
Not in my mind, I am not against scanning the possible
boot devices, on the contrary, I am trying to add booting
the userland from usb instead of mmc for the rpi_b. The
part I dislike is where it starts searching for specific files.
The equivalent would be your BIOS actively searching for GRUB,
LILO, Windows Boot manager etc. etc. and as a fallback
try the MBR.
Also in this case the downstream provides information back,
albeit tiny, it does indicate if it is bootable and a label to explain
what is bootable.
U-Boot performs this searching before having any knowledge of the OS;
there's no way for the OS to parameterize this search path, just like
OSs don't configure a PC BIOS to search a specific HDD/floppy/CDROM
for the MBR to boot.
Yup as said, this is the part I was looking for.
Once U-Boot locates extlinux.conf or boot.scr, that file encodes what
files (kernel, DTB, initrd)
This is the part I get for free now with it, I don't really like it,
since if we take this road it ends up looking for e.g. grub.conf,
ubldr.conf, vxworks.conf etc etc.
I will have a look if I can tame the script, without modifying it nor
u-boot, but I guess that is not possible since boot.scr comes after
extlinux not before.
Regards,
Jeroen
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