Messages in this thread | | | Date | Fri, 13 Sep 2013 14:17:01 -0400 | From | Matt Porter <> | Subject | Re: GPT detection regression in efi.c from commit 27a7c64 |
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On 09/13/2013 01:37 PM, Davidlohr Bueso wrote: > On Fri, 2013-09-13 at 13:01 -0400, Matt Porter wrote: >> On 09/13/2013 12:28 PM, Davidlohr Bueso wrote: > [...] >> >>>> I get that this is not compliant with UEFI. I bring this up because >>>> before this commit the is_pmbr_valid() check was less pedantic. In 3.11 >>>> a PMBR formatted this way did not fail the check. For my particular >>>> case, I simply dded out LBA 1 and whacked the SizeInLBA field to comply >>>> with the spec and this patch and I'm back in business. We're updating >>>> the tools that we inherited to prepopulate our boards with a GPT to be >>>> compliant. However, I wondered if this would be a problem for all the >>>> people with Windows-generated GPTs as noted in [1]. >>> >>> I guess this comes down to choosing whether or not we want Linux to be >>> more UEFI compliant or not. Should we care if Microsoft decides to go do >>> things out of the official spec? I don't know the policy here. The fact >>> is that *they* should update their partitioning tools and create valid >>> pMBRs. Any way, I'm ok with reverting this commit if deemed necessary. >> >> I can't say first-hand that Windows 7/8 does what is claimed in this >> description as I simply don't have access to any Windows machines here. >> If it's true, I would have to agree with Linus that meeting reality if >> more important than meeting the spec. > > Yep, me too. > >> >> Hopefully somebody can confirm that Windows does indeed produce these >> special PMBRs that need to be handled as an exception to the spec. > > I've got a partition with Windows 7 and I can take a look during the > weekend. Do you know exactly what tool was used for creating the > partition?
Just to be clear, we used an internal Broadcom tool that did this Windows-like behavior on our bcm281xx reference board.
In the Windows situation, I really have no idea what tool Windows 7/8 use to partition disks. Based on that article, I'm assuming it's whatever today's version of "FDISK", as shipped on Windows 7/8, is.
Ok, Google claims it is "The Windows 7 Disk Management" tool. I might try to stop at somebody's house this weekend, boot Linux from USB and extract the PMBR from their drive just as another data point.
-Matt
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