Messages in this thread | | | Date | Fri, 29 Jun 2001 22:40:18 +0200 (MET DST) | From | Andries.Brouwer@cwi ... | Subject | Re: Patch(2.4.5): Fix PCMCIA ATA/IDE freeze (w/ PCI add-in cards)V3 |
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Andre Hedrick wrote:
> That is a legacy bit from ATA-2 but it is one of those things you cannot > get rid of :-(
in ANSI X3.279-1996, "AT Attachment Interface with Extensions (ATA-2)", Approved September 11, 1996 , control register bit 3-7 are reserved.
However ANSI X3.221-1994, "AT Attachment Interface for Disk Drives", Approved May 12, 1994, bit3 is "1" and bits 4-7 are "x". No further explanation.
How far back must we go, to get the sense ?
> struct { > unsigned bit0 : 1; > unsigned nIEN : 1; /* device INTRQ to host */ > unsigned SRST : 1; /* host soft reset bit */ > unsigned bit3 : 1; /* ATA-2 thingy */ > unsigned reserved456 : 3; > unsigned HOB : 1; /* 48-bit address ordering */ > } control_t; > > once I add-in the real def of bit3 then I will not > need to look it up again.
bit3: 0: drive has 1-8 heads 1: drive has more than 8 heads
(From old MFM/RLL times. In ATA-1 bit3 is set to 1. See also http://www.win.tue.nl/~aeb/linux/hdtypes/hdtypes-2.html .)
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