[Qemu-devel] [Bug 578346] Re: ATA IDENTIFY DEVICE word 64 doesn't describe available PIO modes

[Aurelien Jarno]

** Changed in: qemu
       Status: New => Fix Committed

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https://bugs.launchpad.net/bugs/578346

Title:
  ATA IDENTIFY DEVICE word 64 doesn't describe available PIO modes

Status in QEMU:
  Fix Committed

Bug description:
  The IDENTIFY DEVICE data provided by Qemu ATA devices lacks good
  information in word 64.  Word 64 describes PIO mode capabilities.
  NetBSD guests (perhaps dubiously) expect to find PIO modes 3 and/or 4
  to be available before enabling Ultra DMA modes on the
  controller/device.  This leads to NetBSD guests using PIO mode 0.

  NetBSD guests will accept values in the range of 0x00 through 0x1f
  (though at least one bit must be set for DMA to be considered) in word
  64. Currently, ide_atapi_identify() sets this word to 0x3f in the
  USE_DMA_CDROM case and 0x01 otherwise. ide_identify() doesn't set this
  word at all.  I recommend that these both be adjusted to 0x3, which
  parallels many real drives in the wild, as well as what a ATA8-ACS
  draft says SATA drives should have in word 64.