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>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c3bfacb..489815e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1456,6 +1456,8 @@
* dump_id: dump IDENTIFY data.
+ * atapi_dmadir: Enable ATAPI DMADIR bridge support
+
If there are multiple matching configurations changing
the same attribute, the last one is used.