Subject: Re: LBA48_THRESHOLD
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 01/15/2005 14:27:12
>> I note in wd.c:  [...LBA48 stuff...]
>>             (wd->sc_wdc_bio.blkno > LBA48_THRESHOLD ||

>> Wouldn't it make more sense for the > to be >=?  ISTM the quirk
>> could go away then.

> No, because it could then break existing setups of drives supporting
> LBA48, but with 0x10000000 sectors (so which don't need LBA48),
> connected to controllers that don't handle LBA48.

I am inclined to doubt any such drives exist; manufacturers generally
go for round *decimal* numbers of bytes, which means they tend to avoid
round *binary* numbers of bytes.

Also, is it possible to report a size of 0x10000000 through LBA?  I
would tend to doubt it, or the ST3200822A presumably would be doing it.

Or am I missing something else?  (I readily admit there's a whole lot
here I do not really understand, so this is fairly likely.)

> However, instead of the quick, we could probably use the LBA sectors
> reported to decide when to switch to LBA48, instead of the quirk.

I'm not sure what you mean.  You mean,
wd->sc-wdc_bio.blkno >= LBA-reported-size?  Or you mean "if
LBA-reported-size is LBA48_THRESHOLD or higher" replacing the "if drive
claims LBA48" test?

The former actually sounds like a pretty good fix.

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