libata: Add atapi_dmadir force flag

Some device require DMADIR to be enabled, but are not detected as such
by atapi_id_dmadir.  One such example is "Asus Serillel 2"
SATA-host-to-PATA-device bridge: the bridge itself requires DMADIR,
even if the bridged device does not.

As atapi_dmadir module parameter can cause problems with some devices
(as per Tejun Heo's memory), enabling it globally may not be possible
depending on the hardware.

This patch adds atapi_dmadir in the form of a "force" horkage value,
allowing global, per-bus and per-device control.

Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 5f7d5f9ee820..c97a244c099a 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2395,7 +2395,7 @@ int ata_dev_configure(struct ata_device *dev)
                         cdb_intr_string = ", CDB intr";
                 }
 
-                if (atapi_dmadir || atapi_id_dmadir(dev->id)) {
+                if (atapi_dmadir || (dev->horkage & ATA_HORKAGE_ATAPI_DMADIR) || atapi_id_dmadir(dev->id)) {
                         dev->flags |= ATA_DFLAG_DMADIR;
                         dma_dir_string = ", DMADIR";
                 }
@@ -6496,6 +6496,7 @@ static int __init ata_parse_force_one(char **cur,
                 { "nosrst",     .lflags         = ATA_LFLAG_NO_SRST },
                 { "norst",      .lflags         = ATA_LFLAG_NO_HRST | ATA_LFLAG_NO_SRST },
                 { "rstonce",    .lflags         = ATA_LFLAG_RST_ONCE },
+                { "atapi_dmadir", .horkage_on   = ATA_HORKAGE_ATAPI_DMADIR },
         };
         char *start = *cur, *p = *cur;
         char *id, *val, *endp;