libata-acpi: improve _GTF execution error handling and reporting

As _GTF commands can't transfer data, device error never signals
transfer error.  It indicates that the device vetoed the operation, so
it's meaningless to retry.

This patch makes libata-acpi to report and continue on device errors
when executing _GTF commands.  Also commands rejected by device don't
contribute to the number of _GTF commands executed.

While at it, update _GTF execution reporting such that all successful
commands are logged at KERN_DEBUG and rename taskfile_load_raw() to
ata_acpi_run_tf() for consistency.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 46 insertions, 31 deletions

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index 5932ae24ddc1..d4cb557a727d 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -466,7 +466,7 @@ int ata_acpi_cbl_80wire(struct ata_port *ap)
 EXPORT_SYMBOL_GPL(ata_acpi_cbl_80wire);
 
 /**
- * taskfile_load_raw - send taskfile registers to host controller
+ * ata_acpi_run_tf - send taskfile registers to host controller
  * @dev: target ATA device
  * @gtf: raw ATA taskfile register set (0x1f1 - 0x1f7)
  *
@@ -485,14 +485,17 @@ EXPORT_SYMBOL_GPL(ata_acpi_cbl_80wire);
  * EH context.
  *
  * RETURNS:
- * 0 on success, -errno on failure.
+ * 1 if command is executed successfully.  0 if ignored or rejected,
+ * -errno on other errors.
  */
-static int taskfile_load_raw(struct ata_device *dev,
-                              const struct ata_acpi_gtf *gtf)
+static int ata_acpi_run_tf(struct ata_device *dev,
+                           const struct ata_acpi_gtf *gtf)
 {
-        struct ata_port *ap = dev->link->ap;
         struct ata_taskfile tf, rtf;
         unsigned int err_mask;
+        const char *level;
+        char msg[60];
+        int rc;
 
         if ((gtf->tf[0] == 0) && (gtf->tf[1] == 0) && (gtf->tf[2] == 0)
             && (gtf->tf[3] == 0) && (gtf->tf[4] == 0) && (gtf->tf[5] == 0)
@@ -512,24 +515,39 @@ static int taskfile_load_raw(struct ata_device *dev,
         tf.device  = gtf->tf[5];        /* 0x1f6 */
         tf.command = gtf->tf[6];        /* 0x1f7 */
 
-        if (ata_msg_probe(ap))
-                ata_dev_printk(dev, KERN_DEBUG, "executing ACPI cmd "
-                               "%02x/%02x:%02x:%02x:%02x:%02x:%02x\n",
-                               tf.command, tf.feature, tf.nsect,
-                               tf.lbal, tf.lbam, tf.lbah, tf.device);
-
         rtf = tf;
         err_mask = ata_exec_internal(dev, &rtf, NULL, DMA_NONE, NULL, 0, 0);
-        if (err_mask) {
-                ata_dev_printk(dev, KERN_ERR,
-                        "ACPI cmd %02x/%02x:%02x:%02x:%02x:%02x:%02x failed "
-                        "(Emask=0x%x Stat=0x%02x Err=0x%02x)\n",
-                        tf.command, tf.feature, tf.nsect, tf.lbal, tf.lbam,
-                        tf.lbah, tf.device, err_mask, rtf.command, rtf.feature);
-                return -EIO;
+
+        switch (err_mask) {
+        case 0:
+                level = KERN_DEBUG;
+                snprintf(msg, sizeof(msg), "succeeded");
+                rc = 1;
+                break;
+
+        case AC_ERR_DEV:
+                level = KERN_INFO;
+                snprintf(msg, sizeof(msg),
+                         "rejected by device (Stat=0x%02x Err=0x%02x)",
+                         rtf.command, rtf.feature);
+                rc = 0;
+                break;
+
+        default:
+                level = KERN_ERR;
+                snprintf(msg, sizeof(msg),
+                         "failed (Emask=0x%x Stat=0x%02x Err=0x%02x)",
+                         err_mask, rtf.command, rtf.feature);
+                rc = -EIO;
+                break;
         }
 
-        return 0;
+        ata_dev_printk(dev, level,
+                       "ACPI cmd %02x/%02x:%02x:%02x:%02x:%02x:%02x %s\n",
+                       tf.command, tf.feature, tf.nsect, tf.lbal,
+                       tf.lbam, tf.lbah, tf.device, msg);
+
+        return rc;
 }
 
 /**
@@ -558,22 +576,19 @@ static int ata_acpi_exec_tfs(struct ata_device *dev, int *nr_executed)
         gtf_count = rc;
 
         /* execute them */
-        for (i = 0, rc = 0; i < gtf_count; i++) {
-                int tmp;
-
-                /* ACPI errors are eventually ignored.  Run till the
-                 * end even after errors.
-                 */
-                tmp = taskfile_load_raw(dev, gtf++);
-                if (!rc)
-                        rc = tmp;
-
-                (*nr_executed)++;
+        for (i = 0; i < gtf_count; i++) {
+                rc = ata_acpi_run_tf(dev, gtf++);
+                if (rc < 0)
+                        break;
+                if (rc)
+                        (*nr_executed)++;
         }
 
         ata_acpi_clear_gtf(dev);
 
-        return rc;
+        if (rc < 0)
+                return rc;
+        return 0;
 }
 
 /**