From: Tejun Heo Date: Wed, 28 Mar 2007 22:33:39 +0000 (-0400) Subject: libata: clear TF before IDENTIFYing X-Git-Tag: v2.6.20.5~6 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=59e23e6198366f057ea49127f810098424d3417c;p=karo-tx-linux.git libata: clear TF before IDENTIFYing libata: clear TF before IDENTIFYing 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 Cc: Art Haas Cc: Mark Lord Cc: Chuck Ebbert Signed-off-by: Jeff Garzik Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 667acd283364..d6fcf0a1b7d8 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);