ide: ide_get_best_pio_mode() returns incorrect IORDY setting (take 2)

The function ide_get_best_pio_mode() fails to return the correct IORDY setting
for the explicitly specified modes -- fix this along with the heading comment,
and also remove the long commented out code.

Also, while at it, correct the misliading comment about the PIO cycle time in
<linux/ide.h> -- it actually consists of only the active and recovery periods,
with only some chips also including the address setup time into equation...

[ bart: sl82c105 seems to be currently the only driver affected by this fix ]

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

2 files changed, 8 insertions, 13 deletions

diff --git a/drivers/ide/ide-lib.c b/drivers/ide/ide-lib.c
index 8afce4ceea31..68719314df3f 100644
--- a/drivers/ide/ide-lib.c
+++ b/drivers/ide/ide-lib.c
@@ -345,16 +345,16 @@ static int ide_scan_pio_blacklist (char *model)
 
 /**
  *      ide_get_best_pio_mode   -       get PIO mode from drive
- *      @driver: drive to consider
+ *      @drive: drive to consider
  *      @mode_wanted: preferred mode
- *      @max_mode: highest allowed
- *      @d: pio data
+ *      @max_mode: highest allowed mode
+ *      @d: PIO data
  *
  *      This routine returns the recommended PIO settings for a given drive,
  *      based on the drive->id information and the ide_pio_blacklist[].
- *      This is used by most chipset support modules when "auto-tuning".
  *
- *      Drive PIO mode auto selection
+ *      Drive PIO mode is auto-selected if 255 is passed as mode_wanted.
+ *      This is used by most chipset support modules when "auto-tuning".
  */
 
 u8 ide_get_best_pio_mode (ide_drive_t *drive, u8 mode_wanted, u8 max_mode, ide_pio_data_t *d)
@@ -367,6 +367,7 @@ u8 ide_get_best_pio_mode (ide_drive_t *drive, u8 mode_wanted, u8 max_mode, ide_p
 
         if (mode_wanted != 255) {
                 pio_mode = mode_wanted;
+                use_iordy = (pio_mode > 2);
         } else if (!drive->id) {
                 pio_mode = 0;
         } else if ((pio_mode = ide_scan_pio_blacklist(id->model)) != -1) {
@@ -396,19 +397,12 @@ u8 ide_get_best_pio_mode (ide_drive_t *drive, u8 mode_wanted, u8 max_mode, ide_p
                         }
                 }
 
-#if 0
-                if (drive->id->major_rev_num & 0x0004) printk("ATA-2 ");
-#endif
-
                 /*
                  * Conservative "downgrade" for all pre-ATA2 drives
                  */
                 if (pio_mode && pio_mode < 4) {
                         pio_mode--;
                         overridden = 1;
-#if 0
-                        use_iordy = (pio_mode > 2);
-#endif
                         if (cycle_time && cycle_time < ide_pio_timings[pio_mode].cycle_time)
                                 cycle_time = 0; /* use standard timing */
                 }
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 79c028251c70..34f2676b3c62 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1359,7 +1359,8 @@ u8 ide_dump_status(ide_drive_t *, const char *, u8);
 typedef struct ide_pio_timings_s {
         int     setup_time;     /* Address setup (ns) minimum */
         int     active_time;    /* Active pulse (ns) minimum */
-        int     cycle_time;     /* Cycle time (ns) minimum = (setup + active + recovery) */
+        int     cycle_time;     /* Cycle time (ns) minimum = */
+                                /* active + recovery (+ setup for some chips) */
 } ide_pio_timings_t;
 
 typedef struct ide_pio_data_s {