* linux/drivers/ide/pci/cs5535.c
  *
  * Copyright (C) 2004-2005 Advanced Micro Devices, Inc.
+ * Copyright (C)      2007 Bartlomiej Zolnierkiewicz
  *
  * History:
  * 09/20/2005 - Jaya Kumar <jayakumar.ide@gmail.com>
 
        /* Set the PIO timings */
        if ((speed & XFER_MODE) == XFER_PIO) {
-               u8 pioa;
-               u8 piob;
-               u8 cmd;
+               ide_drive_t *pair = &drive->hwif->drives[drive->dn ^ 1];
+               u8 cmd, pioa;
 
-               pioa = speed - XFER_PIO_0;
-               piob = ide_get_best_pio_mode(&(drive->hwif->drives[!unit]),
-                                               255, 4);
-               cmd = pioa < piob ? pioa : piob;
+               cmd = pioa = speed - XFER_PIO_0;
+
+               if (pair->present) {
+                       u8 piob = ide_get_best_pio_mode(pair, 255, 4);
+
+                       if (piob < cmd)
+                               cmd = piob;
+               }
 
                /* Write the speed of the current drive */
                reg = (cs5535_pio_cmd_timings[cmd] << 16) |
  *
  *     A callback from the upper layers for PIO-only tuning.
  */
-static void cs5535_tuneproc(ide_drive_t *drive, u8 xferspeed)
+static void cs5535_tuneproc(ide_drive_t *drive, u8 pio)
 {
-       u8 modes[] = {  XFER_PIO_0, XFER_PIO_1, XFER_PIO_2, XFER_PIO_3,
-                       XFER_PIO_4 };
-
-       /* cs5535 max pio is pio 4, best_pio will check the blacklist.
-       i think we don't need to rate_filter the incoming xferspeed
-       since we know we're only going to choose pio */
-       xferspeed = ide_get_best_pio_mode(drive, xferspeed, 4);
-       ide_config_drive_speed(drive, modes[xferspeed]);
-       cs5535_set_speed(drive, xferspeed);
+       pio = ide_get_best_pio_mode(drive, pio, 4);
+       ide_config_drive_speed(drive, XFER_PIO_0 + pio);
+       cs5535_set_speed(drive, XFER_PIO_0 + pio);
 }
 
 static int cs5535_dma_check(ide_drive_t *drive)
 {
-       u8 speed;
-
        drive->init_speed = 0;
 
        if (ide_tune_dma(drive))
                return 0;
 
-       if (ide_use_fast_pio(drive)) {
-               speed = ide_get_best_pio_mode(drive, 255, 4);
-               cs5535_set_drive(drive, speed);
-       }
+       if (ide_use_fast_pio(drive))
+               cs5535_tuneproc(drive, 255);
 
        return -1;
 }