Mark Lord wrote:
Albert Lee wrote:
Tejun Heo wrote:
Back in 2.6.17-rc2, a libata module parameter was added for
atapi_dmadir.
That's nice, but most SATA devices which need it will tell us about it
in their IDENTIFY PACKET response, as bit-15 of word-62 of the
returned data (as per ATA7, ATA8 specifications).
So for those which specify it, we should automatically use the DMADIR
bit.
Otherwise, disc writing will fail by default on many SATA-ATAPI drives.
This patch adds ATA_DFLAG_DMADIR and make ata_dev_configure() set it
if atapi_dmadir is set or identify data indicates DMADIR is necessary.
atapi_xlat() is converted to check ATA_DFLAG_DMADIR before setting
DMADIR.
Original patch is from Mark Lord.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
Cc: Mark Lord <mlord@xxxxxxxxx>
---
I don't have a bridge which sets DMADIR but so only checked atapi_dmadir
parameter. Thanks.
The patch looks good. However, it seems there is no realworld IDE-to-SATA
bridge that requires DMADIR and also mangles IDENTIFY PACKET bit-15 of
word-62 to indicate its presence.
From the previous test of the IDE-to-SATA bridges, only the Sil 3611
requires the host software to hint on ATAPI DMADIR. But Sil 3611 doesn't
mangle IDENTIFY PACKET word-62:
http://www.spinics.net/lists/linux-ide/msg01514.html
..
Ahh, great! We have "history" here!
But there are more SATA bridges out there than the ones Alber has there
(SiI 3611/3811, Marvell 88i8030/88SA8040, Acard ARC770, JMicron JM20330).
There's the Marvell 88SA8050, and I have a funky looking thing here
that says "SataLink SPiF223A" on it (????). I wonder what it does?
And how many other ones are there?
The Word62 patch (from Tejun) is simple enough that the "complexity"
point from before really doesn't hold water.
I'm going to apply Tejun's patch. It's fine (as I noted I conditionally
ACK'd your original patch).
My opinion, though, it that this is merely coding to the spec, rather
than making a bunch of real-world hardware work. All the SATA<->PATA
bridges I have, that support ATAPI, do not flag DMADIR.
Jeff
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