On 01/11/2015 11:15 AM, Tom Rini wrote:
On Sun, Jan 11, 2015 at 10:54:03AM -0700, Stephen Warren wrote:
On 01/11/2015 02:45 AM, Ian Campbell wrote:
On Sun, 2014-12-28 at 09:26 +0000, Ian Campbell wrote:
+boot_scripts:
- The name of U-Boot style boot.scr files that $bootcmd searches for.
- Example: boot.scr.uimg boot.scr
- (Typically we expect extlinux.conf to be used, but execution of boot.scr is
- maintained for backwards-compatibility.)
I'm slightly concerned by the implied deprecation of the boot.scr method here, since at least Debian uses boot.scr exclusively and not the extlinux stuff. Will boot.scr be maintained going forward or are there plans to eventually remove it?
Can someone confirm that there is no long term plan to drop boot.scr support?
extlinux.conf *is* the standard Linux boot process that config_distro_bootcmd.h enables. boot.scr is *not*. The whole point is to introduce a new simple standard that works the same everywhere (for Linux: across boards, across distros, across bootloaders).
Well, the only problem I see with this statement is that, uh, do we have buy-in from Debian?
Well, there was some discussion about standard boot setups on the cross-distro mailing list. I believe someone from Debian is at least familiar with Dennis's proposal to use extlinux.conf as the standard. There was certainly no definitive agreement in those discussions though.
That said, I don't think there's much choice but to standardize on /something/ other than boot.scr. boot.scr really isn't scalable for generic distros (as opposed to board-specific BSPs):
* boot.scr works differently on different boards, since the set of environment variables and U-Boot commands/features available to the script are different. This leads to extremely complex boot.scr implementations that distros each have to maintain.
I suppose we could fix this by standardizing the boot.scr execution environment; providing a consistent set of variables indicating where to load kernel/DTB/..., the board name (to auto-generate DTB filename), etc. However, standardizing this is more complex that standardizing on extlinux.conf and still doesn't solve:
* boot.scr doesn't work across different bootloaders. There's no reason generic distros should know anything much about bootloaders, other than how to generate a config file so the bootloader knows which kernel/initrd/DTB binaries to load.
* boot.scr must be generated (to boot.scr.uimg) using bootloader-specific tools, rather than extlinux.conf, grub.conf, ... all just need the generation of a text file.