Re: Compact flash disk and slave drives in 2.4.2

[Andre Hedrick]

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