Re: Compact flash disk and slave drives in 2.4.2

[Andre Hedrick]

./linux/drivers/ide/ide.c

 * "hdx=flash"          : allows for more than one ata_flash disk to be
 *                              registered. In most cases, only one device
 *                              will be present.

On Tue, 27 Mar 2001, Padraig Brady wrote:

> How do you activate the walk around you describe
> to allow the detection of the slave? hda=ataflash?
> Is this sort of stuff documented anywhere?
> 
> For those interested you also mention it here:
> http://lists.sourceforge.net/archives//linux-usb-devel/2000-August/000929.html
> 
> This describes the other combination that causes
> a problem where you have a normal disk as master
> and the CF as slave:
> http://boudicca.tux.org/hypermail/linux-kernel/2000week25/0973.html
> 
> Again the problem unresolved:
> http://boudicca.tux.org/hypermail/linux-kernel/2000week26/0174.html
> 
> cheers,
> Padraig.
> 
> Andre Hedrick wrote:
> 
> > Because 'real' ATA devices use a signature map the detects presense of
> > master slave during execute diagnostics.  This is done in the BIOS.
> > CFA does no report this correctly and waiting for a 31 second time out is
> > not acceptable.  If you have a complain take it to CFA commitee and have
> > them fix it.
> > 
> > I put in a walk around for having 2 CFA's to allow detection.
> > This will work also if you call it for a CFA+Disk pair.
> > 
> > On Tue, 27 Mar 2001, Padraig Brady wrote:
> > 
> >> OK the following assumes CF never have slaves which is just wrong.
> >> The CF should be logically treated as an IDE harddisk. So the fix is
> >> probably have a kernel parameter that causes the following check to
> >> be skipped?
> > 
> > Logically treated, is true, but again CFA does not follow the rules of
> > what the ATA committee gives them, and I refuse to break rules as the
> > standard model.  Rule breaking are exceptions.
> > 
> > Also show me a case where a laptop will do master/slave in CFA.
> > 
> >> /*
> >>    * Prevent long system lockup probing later for non-existant
> >>    * slave drive if the hwif is actually a flash memory card of some 
> >> variety:
> >>    */
> >>   if (drive_is_flashcard(drive)) {
> >>           ide_drive_t *mate = &HWIF(drive)->drives[1^drive->select.b.unit];
> >>           if (!mate->ata_flash) {
> >>                 mate->present = 0;
> >>                 ide_drive_t *mate = 
> >> &HWIF(drive)->drives[1^drive->select.b.unit]
> >>                 mate->noprobe = 1;
> >>           }
> >>   }
> >> 
> >> But do we need this check? Is it just for speed. If you have an "ordinary"
> >> harddrive as master with no slave, will the check for slave cause the same
> >> "long system lockup", and if not, why.
> >> 
> >> Padraig.
> >> 
> >> Andre Hedrick wrote:
> >> 
> >> 
> >>> Because in laptops, the primary use of CFA.
> >>> Laptops using CFA do not have slaves.
> >> 
> > 
> > Andre Hedrick
> > Linux ATA Development
> > ASL Kernel Development
> > -----------------------------------------------------------------------------
> > ASL, Inc.                                     Toll free: 1-877-ASL-3535
> > 1757 Houret Court                             Fax: [phone]
> > Milpitas, CA 95035                            Web: www.aslab.com
> 

Andre Hedrick
Linux ATA Development
ASL Kernel Development
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