Messages in this thread | | | Date | Sat, 30 Jun 2001 01:14:36 -0700 (PDT) | From | Andre Hedrick <> | Subject | Re: Patch(2.4.5): Fix PCMCIA ATA/IDE freeze (w/ PCI add-in cards)V3 |
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Okay my bad it is ATA-1 but even that does not explain the bit. only that section 7.2.6 top of page 14 (index numbers) defines it to be set to 1 with out a reason.
This this is a pre-ATA thing back in IDE.
If you really want to know the answer I can go dig it up, but later.
Cheers,
Andre Hedrick ASL Kernel Development Linux ATA Development ----------------------------------------------------------------------------- ASL, Inc. Toll free: 1-877-ASL-3535 1757 Houret Court Fax: 1-408-941-2071 Milpitas, CA 95035 Web: www.aslab.com
On Fri, 29 Jun 2001, Gunther Mayer wrote:
> Andre Hedrick wrote: > > > > That is a legacy bit from ATA-2 but it is one of those things you can not > > get rid of :-( even thou things are obsoleted, they are not retired. > > This means that you have to go back into the past to see how it was used, > > silly! I hope you agree to that point. > > No, > 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 ? > > > > > This is the drive->ctrl register pointer. > > > > outp(drive->ctl|0x02, IDE_CONTROL_REG); > > > > typedef union { > > unsigned all : 8; /* all of the bits together */ > > 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 */ > > } b; > > } control_t; > > > > This is a new struct that is to be added for 48-bit addressing and it will > > reflect drive->ctl soon. I have not decided how to use it best or at all, > > but it has meaning and once I add-in the real def of bit3 then I will not > > need to look it up again. >
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