Re: [PATCH] EDD: Check for correct EDD 3.0 length

From: Gleb Natapov
Date: Tue May 15 2012 - 08:53:58 EST


On Tue, May 15, 2012 at 02:59:17PM +0300, Gleb Natapov wrote:
> > So why do you claim we can't display it anymore?
> >
> Before commit 0c61227094b3ddaca2f847ee287c4a2e3762b5a2 the code didn't
> calculate checksum correctly. The check always succeed, so when bios
> provided information according to T13 EDD4.0 spec interface_type contained
Correction. If BIOS provided information _not_ according to T13 EDD4.0 spec
interface_type contained garbage since the reset of the code assumes the
EDD4.0 information.

Looked like that:
# cat /sys/firmware/edd/int13_dev80/interface
SCSI id: 0 lun: 1224979098644774912

> garbage. After the commit checksum is calculated correctly, but according
> to T13 EDD4.0 spec, so for BIOSes that supply info according to another
> spec check fails. Since T13 EDD4.0 spec support modern interfaces (RAID,
> SATA, SAS) which another spec omits, and for interfaces they both support
> T13 EDD4.0 actually supply enough information to link edd entry to actual
> device (another spec does not), I do not see support for other spec to
> be important, but you are welcome to write support for it if you need
> it. The only way I see to check what spec edd info corresponds to is to
> calculate checksum according to both specs and see which one succeeds.
>
> --
> Gleb.
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--
Gleb.
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