On 08/22/2012 06:12 PM, Stephen Warren wrote:
> On 08/22/2012 01:11 PM, Rob Herring wrote:
>> On 08/21/2012 10:58 PM, Stephen Warren wrote:
>>> On 08/08/2012 12:30 PM, Rob Herring wrote:
>>> ...
>>>> Making u-boot more intelligent discovering things also helps here. For 
>>>> example, 
>>>> booting from the disk partition with the bootable flag set. I've submitted 
>>>> patches for this a while back.
>>>
>>> That sounds like these:
>>>
>>> http://www.mail-archive.com/[email protected]/msg79100.html
>>>
>>> Is it likely these will make it into U-Boot? Nobody seems to have
>>> replied to your patches.
>>
>> Not likely, they've bit-rotted and there's at least one issue I've
>> fixed. I need to repost the series, but the overwhelming response on the
>> first posting doesn't motivate me.
> 
> Do you want me to pick them up (i.e. do the rebase, etc.)?
> 
>>> I just recently proposed a "partuuid" command to extract a partition's
>>> UUID, but I've since re-written it to be a "part" command with a "uuid"
>>> sub-command. Adding a "get-bootable" sub-command to retrieve the flag
>>> your patch sets would be a good idea. Should I pull your patches into my
>>> series to do this?
>>>
>>> Your series only implements bootable flag retrieval for MSDOS/MBR
>>> partitions. I wonder what flag one should key off for EFI/GPT partition
>>> tables? Looking at parted/gparted, the following options exist:
>>>
>>> A parted flag called "boot", which sets the partition's type UUID. This
>>> appears to have been supported since before parted was in git (i.e. 2006
>>> some time).
>>>
>>> A parted flag called "legacy_boot", which actually sets a single bit in
>>> the partition attributes. This feature is available in parted v2.4 and
>>> later, which isn't even in Ubuntu Quantal yet, although it was released
>>> a while ago. This seems to be the more correct option, although not very
>>> available to users.
>>>
>>> Perhaps either case should trigger U-Boot to consider the partition
>>> bootable?
>>
>> I only briefly looked at EFI partitioning. My conclusion was some EFI
>> variable gets set to point to the boot loader, but if there's bootable
>> flags that's better for u-boot. I haven't worried about it because I
>> can't even get debian installer to use EFI partitions. It's partitioning
>> config basically says if the arch is arm, use DOS partitions.
> 
> I'm more talking about pure EFI/GPT partitions on a disk here, rather
> than a full EFI environment. In other words, U-Boot is the entirety of
> the firmware, and it's reading the partition table directly.

Right. But I'm just wondering how typical the boot or legacy boot flags
are. If those are not used in a "standard" boot process, then it's
probably not worth getting u-boot to use them depending on your end goal.

Rob

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