libata: add command name parsing for error output

This patch improve libata's output for error/notification messages
to allow easier comprehension and debugging:

When ATAPI commands issued through the SCSI layer fail, use SCSI
functions to print the CDB in human-readable form instead of just
dumping out the CDB in hex.

Print out the name of the failed command (as defined by the ATA
specification) in error handling output along with the raw register
contents.

When reporting status of ACPI taskfile commands executed on resume,
also output the names of the commands being executed (or not) in
readable form.

Since the extra data for printing command names increases kernel
size slightly, a config option has been added to allow disabling
command name output (as well as some of the error register parsing)
for those highly sensitive to kernel text size.

Signed-off-by: Robert Hancock <hancockrwd@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index ac176da1f94..01964b6e6f6 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -689,6 +689,7 @@ static int ata_acpi_run_tf(struct ata_device *dev,
 	struct ata_taskfile tf, ptf, rtf;
 	unsigned int err_mask;
 	const char *level;
+	const char *descr;
 	char msg[60];
 	int rc;
 
@@ -736,11 +737,13 @@ static int ata_acpi_run_tf(struct ata_device *dev,
 		snprintf(msg, sizeof(msg), "filtered out");
 		rc = 0;
 	}
+	descr = ata_get_cmd_descript(tf.command);
 
 	ata_dev_printk(dev, level,
-		       "ACPI cmd %02x/%02x:%02x:%02x:%02x:%02x:%02x %s\n",
+		       "ACPI cmd %02x/%02x:%02x:%02x:%02x:%02x:%02x (%s) %s\n",
 		       tf.command, tf.feature, tf.nsect, tf.lbal,
-		       tf.lbam, tf.lbah, tf.device, msg);
+		       tf.lbam, tf.lbah, tf.device,
+		       (descr ? descr : "unknown"), msg);
 
 	return rc;
 }