Hi Jeff, It appears that commit 7b3a24c57d2eeda8dba9c205342b12689c4679f9 broke CD-ROMs on the IPR SATA bus on powerpc machines: ata_port_alloc: ENTER ata_port_probe: ata1: bus probe begin ata1.00: ata_dev_read_id: ENTER ata1.00: failed to IDENTIFY (I/O error, err_mask=0x40) ata1.00: ata_dev_read_id: ENTER ata1.00: failed to IDENTIFY (I/O error, err_mask=0x40) ata1.00: limiting speed to UDMA7:PIO5 ata1.00: ata_dev_read_id: ENTER ata1.00: failed to IDENTIFY (I/O error, err_mask=0x40) ata1.00: disabled ata_port_probe: ata1: bus probe end scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured The commit in question is tagged as AHCI, but does touch the libata core. I'm not well-versed with this code, but here's what I think I know :) >From __scsi_add_device, we first allocate the target: scsi_alloc_target -> shost->hostt->target_alloc -> ipr_target_alloc -> ata_port_alloc -> sets FROZEN We error out when we allocate the sdev: scsi_alloc_sdev -> shost->hostt->slave_alloc -> ipr_slave_alloc -> ipr_ata_slave_alloc -> ata_sas_port_init -> ata_port_probe >From what I can tell, the only place that explicitly clears the FROZEN flag is the error-handling code via ata_eh_thaw_port(). So I thought either we're not invoking the error-handler at probe time correctly to kick the port or perhaps the SAS code is not clearing the flag? I tried the following patch: diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index d51f979..abd0e0b 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -3797,6 +3797,7 @@ EXPORT_SYMBOL_GPL(ata_sas_port_alloc); */ int ata_sas_port_start(struct ata_port *ap) { + ap->pflags &= ~ATA_PFLAG_FROZEN; return 0; } EXPORT_SYMBOL_GPL(ata_sas_port_start); and the CD-ROM drive works, but I have no idea if it's the right thing to do. I chose this particular change, FWIW, because we call ata_sas_port_start before we probe in ata_sas_port_init and it seems like we need to mark the port as not frozen before we init it? Perhaps that should really be a call to a thaw function, not sure. Let's just say the ATA/SAS/SCSI interactions are a bit hard to follow at first :) Any insight you can provide would be great! Thanks, Nish -- Nishanth Aravamudan <nacc@xxxxxxxxxx> IBM Linux Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html