Hello.
Mark Lord wrote:
The fussy bit is that these commands require a non-standard
sector size, usually 520 bytes instead of 512.
Which requires from the drivers to be able to turn off IDE prefetch
(and maybe posting too). I don't see that in this patch (or are you
expecting them to just "snoop' the commands and do it automagically?).
Most controllers seem to be behave well enough
and just not muck up. And if it fails on any "too clever" controllers,
then no big deal -- we just switch to a controller that works instead.
IDE controllers are generally not known as "clever" -- and that's what's
frightening me... :-)
This is not an essential command for normal operation.
What it is for, is injecting errors so that we can experience
firsthand the (excellent or crappy) error handling in the kernel
and in applications. And then work out and test better strategies.
So 100% working everywhere, for an obsolete opcode, isn't really
essential to me. But it should work most places, and it does.
I don't think it should *correctly* work anywhere w/prefetch on, IDE bus
wise. Maybe that just doesn't show up on host side (but well might have been).
Again, ata_data_xfer() doesn't seem capable of performing ECC
read/writes
-- the ECC bytes must be transferred in 8-bit mode, AFAIR.
ata_data_xfer()
can oinly do that for optionally trailing odd byte.
I have no idea what that was all about. Care to explain again?
Care to read the standards? :-/
RWLONG transfer the ECC info 8-bits at a time, using 16-bit words
to do so, no different from normal. ???
From ATA-1:
"The transfer of the vendor specific bytes shall be one byte at a time
over bits DD0-7 only (8-bits wide)."
Here it is again with the whitespace not so messed up.
I'm sorry, it seems only being messed on my side, due to format=flowed. :-/
The READ/WRITE LONG commands are theoretically obsolete,
but the majority of drives in existance still implement them.
The WRITE_LONG and WRITE_LONG_ONCE commands are of particular
interest for fault injection testing -- eg. creating "media errors"
at specific locations on a disk.
The fussy bit is that these commands require a non-standard
sector size, usually 520 bytes instead of 512.
It's 516 bytes, not 512 as you claim. Well, maybe the extra odd bytes
don't matter anyway in this GIGO case... :-)
This patch adds support to libata for READ/WRITE LONG commands
issued via SG_IO/ATA_16.
This patch was generated against a 2.6.21-rc3-git7 base:
MBR, Sergei
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