[PATCH] ide: option to disable cache flushes for buggy drives

Some drives claim they support cache flushing, but get seriously
confused if you try. Add this option to be able to boot with
barriers enabled by default.

Signed-off-by: Jens Axboe <axboe@suse.de>

3 files changed, 6 insertions, 2 deletions

diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index f712e4cfd9dc..7cf3eb023521 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -776,7 +776,7 @@ static void update_ordered(ide_drive_t *drive)
                  * not available so we don't need to recheck that.
                  */
                 capacity = idedisk_capacity(drive);
-                barrier = ide_id_has_flush_cache(id) &&
+                barrier = ide_id_has_flush_cache(id) && !drive->noflush &&
                         (drive->addressing == 0 || capacity <= (1ULL << 28) ||
                          ide_id_has_flush_cache_ext(id));
 
diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 05fbd9298db7..defd4b4bd374 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -1539,7 +1539,7 @@ static int __init ide_setup(char *s)
                 const char *hd_words[] = {
                         "none", "noprobe", "nowerr", "cdrom", "serialize",
                         "autotune", "noautotune", "minus8", "swapdata", "bswap",
-                        "minus11", "remap", "remap63", "scsi", NULL };
+                        "noflush", "remap", "remap63", "scsi", NULL };
                 unit = s[2] - 'a';
                 hw   = unit / MAX_DRIVES;
                 unit = unit % MAX_DRIVES;
@@ -1578,6 +1578,9 @@ static int __init ide_setup(char *s)
                         case -10: /* "bswap" */
                                 drive->bswap = 1;
                                 goto done;
+                        case -11: /* noflush */
+                                drive->noflush = 1;
+                                goto done;
                         case -12: /* "remap" */
                                 drive->remap_0_to_1 = 1;
                                 goto done;
diff --git a/include/linux/ide.h b/include/linux/ide.h
index dc7abef10965..99620451d958 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -571,6 +571,7 @@ typedef struct ide_drive_s {
         u8      waiting_for_dma;        /* dma currently in progress */
         u8      unmask;                 /* okay to unmask other irqs */
         u8      bswap;                  /* byte swap data */
+        u8      noflush;                /* don't attempt flushes */
         u8      dsc_overlap;            /* DSC overlap */
         u8      nice1;                  /* give potential excess bandwidth */