Re: Possible regression of LBA48 support for piix

[Mikael Pettersson]

Romain Kubany writes:
 > Hello,
 > 
 > We are using Microsoft Hyper-V Virtualization technology for some of our GNU/Linux guests and we recently discovered 
 > that the emulated hardware does not seem to support LBA48 adressing on IDE controller.
 > 
 > After some tests, here are the results on a VM with a 200GB virtual disk : disk is detected as 214748MB up to kernel 2.6.27.41 and as 136899MB in 2.6.28 and up.
 > 
 > The two kernels (2.6.27.41 and 2.6.28) were compiled with approximatively the same parameters (just an oldconfig between them, I'll paste a line to their respective config at the end of the mail)
 > except that many changes occured in IDE management between 2.6.27 and 2.6.28 series of the kernel so it is possible that the problem is coming from a misconfiguration on our side (in which case I'll present you my truthful apologies for making you waste your time).
 > 
 > Here are some useful informations (I think) for start :
 > 
 > [On the "working" kernel, 2.6.27.41 w/ 200GB recognized vdisk]
 > 
 > # hdparm -I /dev/hda

Try using libata and ata_piix instead of the old IDE drivers, but
be aware that the disk will show up as /dev/sda not /dev/hda.

Also, IDE/ATA-related issues should be cc:d to linux-ide (see MAINTAINERS).
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