ide: relax DMA info validity checking

commit 346c17a6cf60375323adfaa4b8a9d841049f890e upstream.

There are some broken devices that report multiple DMA xfer modes
enabled at once (ATA spec doesn't allow it) but otherwise work fine
with DMA so just delete ide_id_dma_bug().

[ As discovered by detective work by Frans and Bart, due to how
  handling of the ID block was handled before commit c419993
  ("ide-iops: only clear DMA words on setting DMA mode") this
  check was always seeing zeros in the fields or other similar
  garbage.  Therefore this check wasn't actually checking anything.
  Now that the tests actually check the real bits, all we see are
  devices that trigger the check yet work perfectly fine, therefore
  killing this useless check is the best thing to do. -DaveM ]

Reported-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index a0b8cab1d9a682249200fce35bc5ea5c8223079f..3194e1d0587f8d19e637a1f3ea8b0d3f4aca80e1 100644 (file)
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -362,9 +362,6 @@ static int ide_tune_dma(ide_drive_t *drive)
        if (__ide_dma_bad_drive(drive))
                return 0;
 
-       if (ide_id_dma_bug(drive))
-               return 0;
-
        if (hwif->host_flags & IDE_HFLAG_TRUST_BIOS_FOR_DMA)
                return config_drive_for_dma(drive);
 
@@ -395,24 +392,6 @@ static int ide_dma_check(ide_drive_t *drive)
        return -1;
 }
 
-int ide_id_dma_bug(ide_drive_t *drive)
-{
-       u16 *id = drive->id;
-
-       if (id[ATA_ID_FIELD_VALID] & 4) {
-               if ((id[ATA_ID_UDMA_MODES] >> 8) &&
-                   (id[ATA_ID_MWDMA_MODES] >> 8))
-                       goto err_out;
-       } else if ((id[ATA_ID_MWDMA_MODES] >> 8) &&
-                  (id[ATA_ID_SWDMA_MODES] >> 8))
-               goto err_out;
-
-       return 0;
-err_out:
-       printk(KERN_ERR "%s: bad DMA info in identify block\n", drive->name);
-       return 1;
-}
-
 int ide_set_dma(ide_drive_t *drive)
 {
        int rc;

diff --git a/drivers/ide/ide-iops.c b/drivers/ide/ide-iops.c
index 06fe002116ecc733a1015216d7676e4b24439070..dd5c557175418c0aa22509b66426bfe5cd578e07 100644 (file)
--- a/drivers/ide/ide-iops.c
+++ b/drivers/ide/ide-iops.c
@@ -306,9 +306,6 @@ int ide_driveid_update(ide_drive_t *drive)
 
        kfree(id);
 
-       if ((drive->dev_flags & IDE_DFLAG_USING_DMA) && ide_id_dma_bug(drive))
-               ide_dma_off(drive);
-
        return 1;
 out_err:
        SELECT_MASK(drive, 0);

diff --git a/include/linux/ide.h b/include/linux/ide.h
index 9fed365a598b89845d83271f93d9fe3affef15f2..ca051f3c125cb70915762c704add418f3e16c21b 100644 (file)
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1384,7 +1384,6 @@ int ide_in_drive_list(u16 *, const struct drive_list_entry *);
 #ifdef CONFIG_BLK_DEV_IDEDMA
 int ide_dma_good_drive(ide_drive_t *);
 int __ide_dma_bad_drive(ide_drive_t *);
-int ide_id_dma_bug(ide_drive_t *);
 
 u8 ide_find_dma_mode(ide_drive_t *, u8);
 
@@ -1425,7 +1424,6 @@ void ide_dma_lost_irq(ide_drive_t *);
 ide_startstop_t ide_dma_timeout_retry(ide_drive_t *, int);
 
 #else
-static inline int ide_id_dma_bug(ide_drive_t *drive) { return 0; }
 static inline u8 ide_find_dma_mode(ide_drive_t *drive, u8 speed) { return 0; }
 static inline u8 ide_max_dma_mode(ide_drive_t *drive) { return 0; }
 static inline void ide_dma_off_quietly(ide_drive_t *drive) { ; }