Commit f31f0cc2 authored by Jeff Garzik's avatar Jeff Garzik

[libata] change master/slave IDENTIFY order

2.6.21-rc has horrible problems with libata and PATA cable types (and
thus speeds). This occurs because Tejun fixed a pile of other bugs and
we now do cable detect enforcement for drive side detection properly.

Unfortunately we don't do the process around cable detection right. Tejun
identified the problem and pointed to the right Annex in the spec, this patch
implements the needed changes.

The basic requirement is that we have to identify the slave before the

The patch switches the identify order so that we can do the drive side
detection correctly.

[NOTE: patch and description extracted from a larger work written
and signed-off-by Alan Cox]
Signed-off-by: default avatarJeff Garzik <>
parent 032af1ce
......@@ -1850,8 +1850,11 @@ int ata_bus_probe(struct ata_port *ap)
for (i = 0; i < ATA_MAX_DEVICES; i++)
ap->device[i].pio_mode = XFER_PIO_0;
/* read IDENTIFY page and configure devices */
for (i = 0; i < ATA_MAX_DEVICES; i++) {
/* read IDENTIFY page and configure devices. We have to do the identify
specific sequence bass-ackwards so that PDIAG- is released by
the slave device */
for (i = ATA_MAX_DEVICES - 1; i >= 0; i--) {
dev = &ap->device[i];
if (tries[i])
......@@ -1864,6 +1867,15 @@ int ata_bus_probe(struct ata_port *ap)
if (rc)
goto fail;
/* After the identify sequence we can now set up the devices. We do
this in the normal order so that the user doesn't get confused */
for(i = 0; i < ATA_MAX_DEVICES; i++) {
dev = &ap->device[i];
if (!ata_dev_enabled(dev))
ap->eh_context.i.flags |= ATA_EHI_PRINTINFO;
rc = ata_dev_configure(dev);
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment