Re: Compact flash disk and slave drives in 2.4.2

Padraig Brady (
Tue, 27 Mar 2001 19:50:58 +0100

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:

This describes the other combination that causes
a problem where you have a normal disk as master
and the CF as slave:

Again the problem unresolved:


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: 1-408-941-2071
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