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 - : send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
