Some devices chock if Feature is not clear when IDENTIFY is issued. Set ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE for IDENTIFY such that whole TF is cleared when reading ID data. Kudos to Art Haas for testing various futile patches over several months and Mark Lord for pointing out the fix. Signed-off-by: Tejun Heo <htejun@xxxxxxxxx> Cc: Art Haas <ahaas@xxxxxxxxxxx> Cc: Mark Lord <mlord@xxxxxxxxx> --- I think this should go into -stable but a little bit hesitant because the code hasn't been tested widely. This patch should really be harmless but who knows. Jeff, Mark, what do you think? diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 667acd2..d6fcf0a 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -1478,7 +1478,16 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class, } tf.protocol = ATA_PROT_PIO; - tf.flags |= ATA_TFLAG_POLLING; /* for polling presence detection */ + + /* Some devices choke if TF registers contain garbage. Make + * sure those are properly initialized. + */ + tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; + + /* Device presence detection is unreliable on some + * controllers. Always poll IDENTIFY if available. + */ + tf.flags |= ATA_TFLAG_POLLING; err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE, id, sizeof(id[0]) * ATA_ID_WORDS); - 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
