Alan Cox wrote:
> Found these by inspection:
> 
> Command issuing goes via ata_qc_reinit() which sets up the device bits
> for the command to include the device select bit.
> 
> If we are using NCQ then the code in ata_build_rw_tf sets bit 6 directly
> without using |= which clears the device select bit and means any NCQ
> command will go to the first device regardless.
> 
> The non NCQ path thankfully doesn't blat the other bits and right now we
> have no slave devices on NCQ supporting hardware I believe.

The code is actually intended that way.  The NCQ spec mandates the bit
to be zero.  The device/head register layout is..

 FUA  1  Res  0  Res Res Res Res

We probably need better comment there tho.

-- 
tejun
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