Re: ICH8 and SATA

[Albert Lee <albertcc@tw.ibm.com>]

Tejun Heo wrote:
> Jeff Garzik wrote:
> 
>> BTW, Intel sez:
>>
>> "FYI, I added PIIX_FLAG_IGNORE_PCS and was able to boot on ICH8."
>>
> 
> Yeap, that should achieve about the same effect as the experimental
> patch Andrew posted; also, about the same phantom bug.
> 
> I don't think the phantom device problem is caused by missing
> dev_select.  We have enough dev_select() during classification.
> 

Yes, I cannot find missing dev_select(), neither.

It seems the Intel chip is emulating the PATA master/slave
behavior and reproduces the phantom slave problem of PATA.

>From the ATA-4 spec:
(http://t13.org/project/d1153r18-ATA-ATAPI-4.pdf)

Section 9.16 said: in single master configuration, the master should
response for slave, if the slave is inexistent.
=> The software sees the illusion faked by the master device.

Later in ATA-6 spec, section 9.16 is updated:  for ATAPI devices,
the master should response for slave with 0x00 taskfile,
if the slave if inexistent. However, some device doesn't follow the
new spec...

--
albert

Excertp from the ATA-4 spec:

9.16 Single device configurations

9.16.1 Device 0 only configurations

In a single device configuration where Device 0 is the only device and
the host selects Device 1, Device 0 shall respond as follows:
1) A write to the Device Control register shall complete as if Device 0 was the selected device;
2) A write to a Command Block register, other than the Command register, shall complete as if
Device 0 was selected;
3) A write to the Command register shall be ignored, except for EXECUTE DEVICE DIAGNOSTIC;
4) A read of the Control Block or Command Block registers, other than the Status or Alternate
Status registers, shall complete as if Device 0 was selected;
5) A read of the Status or Alternate status register shall return the value 00h.

NOTE - Even though Device 1 is not present, the register content may appear valid for
Device 1. Further means may be necessary to determine the existence of Device 1, e.g.,
issuing a command.

9.16.2 Device 1 only configurations