Re: GRUB and OLPC

[James Cameron <quozl@laptop.org>]

On Mon, Apr 08, 2013 at 12:45:25AM +0200, Vladimir '??-coder/phcoder' Serbinenko wrote:
> P.S: attitude of OFW devs of rejecting even an idea of GRUB for OLPC
> like I've just experienced on IRC isn't helpful.

I do apologise if my seeking for information appeared to be rejecting
the idea of GRUB for OLPC XO-1.  I really had no idea what you were
talking about, and you had to teach me first.  Since I am very
familiar with how OFW boots Linux, and not at all familiar how GRUB
boots FreeBSD, I am obviously biased toward OFW doing the task.

I look forward to hearing from users of GRUB booting on XO-1.  It
sounds like an interesting challenge.

--> phcoder (~phcoder@245-188.1-85.cust.bluewin.ch) has joined #olpc
<phcoder> Hello, all. Is anybody uses / is interested / finds interesting / ... GRUB2 OLPC support?
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<Quozl> grub is for PC BIOS, but OLPC XO has non-PC BIOS, therefore grub seems irrelevant.  what feature of grub are you looking for?
<phcoder> Quozl: wrong. Platforms currently supported by GRUB:
<phcoder> GRUB_PLATFORMS = [ "emu", "i386_pc", "i386_efi", "i386_qemu", "i386_coreboot",
<phcoder>                    "i386_multiboot", "i386_ieee1275", "x86_64_efi",
<phcoder>                    "mips_loongson", "sparc64_ieee1275",
<phcoder>                    "powerpc_ieee1275", "mips_arc", "ia64_efi",
<phcoder>                    "mips_qemu_mips" ]
<phcoder> 2 more in merge queue, yet one more in developpement
<Quozl> What would be the point?
<Quozl> (i'm willing to be convinced there is a valid purpose, but for the moment i can't see one).
<phcoder> I think you don't see the current situation: OLPC is supported by GRUB2. The question is whether this support should be dropped as OLPC dies out and distances itself from geeks.
<Quozl> I can't see OLPC in the GRUB_PLATFORMS, can you?
<phcoder> i386-ieee1275 is OLPC
<Quozl> Neato.  How could I have known that?
<phcoder> ieee1275 is openfirmware
<Quozl> I couldn't speak for the users of said support.  I've never used it, since the Open Firmware we have includes the necessary code to load kernel and ramdisk of any number of Linux instances.
<Quozl> Why was i386-ieee1275 added?
<phcoder> But not e.g. FreeBSD
<phcoder> And it's easier to adapt existing distro by simply changing installed GRUB flavour that dancing with OFW.
<Quozl> I'm sure Open Firmware could boot FreeBSD if somebody tried hard enough.
--> PhoenixSTF (~rudi@83.240.154.11) has joined #olpc
<Quozl> So the choice is between dancing with GRUB or dancing with Open Firmware?  I'm biased, I'd always dance with Open Firmware.  So you should not ask me my opinion, as I have no relevant experience.
<Quozl> Seems like a waste of time to have Open Firmware transfer control to GRUB only to have GRUB ask Open Firmware to read certain sectors and transfer control to something else.
<Quozl> How quickly does this combination boot?
<Quozl> No ARM support?
<phcoder> Quozl: let me explain: all OLPC-grub devs have gone inactive, that's why the question of retiring the port is on the table in the first place. None of devs even has OLPC. The tests on i386-ieee1275 are performed at best in qemu but your OFW flavour seems to work well only with OLPC, despite claiming to work on qemu and coreboot as well (I tested both)
<Quozl> Show me the tests?
<phcoder> On coreboot it plainly doesn't see the disks (no AHCI support). Couldn't go any further from there.
<phcoder> On qemu it overwrites 1M-1.5M range despite it being marked as usable
<cjb> phcoder: someone on devel@lists.laptop.org might be interested in helping
<phcoder> perhaps sth more. I workarounded the ofw-qemu bugs to make our automated tests run.
<cjb> it seems clear that Quozl isn't :-)
<Quozl> Are you sure this isn't breakage caused by qemu?  ;-)
<Quozl> I've not used coreboot.  I'm just grabbing grub2 sources to find these tests.
<phcoder> cjb: I'm composing a mail now to grub-devel, devel@lists.laptop.org and testing@lists.laptop.org to see if there is a way to reasonably keep it around
<cjb> sounds good, thanks
<phcoder> Quozl: on ofw-i386 they are not automated: I gave up when searching for a way to boot grub.elf directly rather than going to prompt
<Quozl> Automate by creating a directory boot and a file olpc.fth in it that names grub.elf in place of the kernel?
<phcoder> Shipping price to Europe doubles the price of OLPC XO-1
<phcoder> I don't speak forth
<Quozl> You can learn.
<phcoder> Quozl: I'm not interested in it.
<Quozl> Okay.

-- 
James Cameron
http://quozl.linux.org.au/