[PATCH] ide should check dma_on

drivers/ide/ide.c

@@ -1255,13 +1255,14 @@ static int set_io_32bit(ide_drive_t *drive, int arg)
 
 static int set_using_dma (ide_drive_t *drive, int arg)
 {
-	if (!drive->driver || !DRIVER(drive)->supports_dma)
+	if (!DRIVER(drive)->supports_dma)
 		return -EPERM;
 	if (!drive->id || !(drive->id->capability & 1))
 		return -EPERM;
 	if (HWIF(drive)->ide_dma_check == NULL)
 		return -EPERM;
 	if (arg) {
+		if (HWIF(drive)->ide_dma_check(drive)) return -EIO;
 		if (HWIF(drive)->ide_dma_on(drive)) return -EIO;
 	} else {
 		if (HWIF(drive)->ide_dma_off(drive)) return -EIO;