1 files changed, 21 insertions, 11 deletions

diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index f073ea35da00..6000c08f51ba 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -653,7 +653,7 @@ static const u8 xfer_mode_bases[] = {
         XFER_SW_DMA_0,
 };
 
-static unsigned int ide_get_mode_mask(ide_drive_t *drive, u8 base)
+static unsigned int ide_get_mode_mask(ide_drive_t *drive, u8 base, u8 req_mode)
 {
         struct hd_driveid *id = drive->id;
         ide_hwif_t *hwif = drive->hwif;
@@ -670,8 +670,13 @@ static unsigned int ide_get_mode_mask(ide_drive_t *drive, u8 base)
                         mask = hwif->ultra_mask;
                 mask &= id->dma_ultra;
 
-                if ((mask & 0x78) && (eighty_ninty_three(drive) == 0))
-                        mask &= 0x07;
+                /*
+                 * avoid false cable warning from eighty_ninty_three()
+                 */
+                if (req_mode > XFER_UDMA_2) {
+                        if ((mask & 0x78) && (eighty_ninty_three(drive) == 0))
+                                mask &= 0x07;
+                }
                 break;
         case XFER_MW_DMA_0:
                 if ((id->field_valid & 2) == 0)
@@ -709,15 +714,18 @@ static unsigned int ide_get_mode_mask(ide_drive_t *drive, u8 base)
 }
 
 /**
- *      ide_max_dma_mode        -       compute DMA speed
+ *      ide_find_dma_mode       -       compute DMA speed
  *      @drive: IDE device
+ *      @req_mode: requested mode
+ *
+ *      Checks the drive/host capabilities and finds the speed to use for
+ *      the DMA transfer.  The speed is then limited by the requested mode.
  *
- *      Checks the drive capabilities and returns the speed to use
- *      for the DMA transfer.  Returns 0 if the drive is incapable
- *      of DMA transfers.
+ *      Returns 0 if the drive/host combination is incapable of DMA transfers
+ *      or if the requested mode is not a DMA mode.
  */
 
-u8 ide_max_dma_mode(ide_drive_t *drive)
+u8 ide_find_dma_mode(ide_drive_t *drive, u8 req_mode)
 {
         ide_hwif_t *hwif = drive->hwif;
         unsigned int mask;
@@ -728,7 +736,9 @@ u8 ide_max_dma_mode(ide_drive_t *drive)
                 return 0;
 
         for (i = 0; i < ARRAY_SIZE(xfer_mode_bases); i++) {
-                mask = ide_get_mode_mask(drive, xfer_mode_bases[i]);
+                if (req_mode < xfer_mode_bases[i])
+                        continue;
+                mask = ide_get_mode_mask(drive, xfer_mode_bases[i], req_mode);
                 x = fls(mask) - 1;
                 if (x >= 0) {
                         mode = xfer_mode_bases[i] + x;
@@ -738,10 +748,10 @@ u8 ide_max_dma_mode(ide_drive_t *drive)
 
         printk(KERN_DEBUG "%s: selected mode 0x%x\n", drive->name, mode);
 
-        return mode;
+        return min(mode, req_mode);
 }
 
-EXPORT_SYMBOL_GPL(ide_max_dma_mode);
+EXPORT_SYMBOL_GPL(ide_find_dma_mode);
 
 int ide_tune_dma(ide_drive_t *drive)
 {