tree aff0dd3b2db8856aba533c7421acb78847f072e3
parent 9309049544935f804b745aa4dea043fb39b2bf2a
author Martin Wilck <martin.wilck@fujitsu-siemens.com> 1123139096 +0200
committer Jeff Garzik <jgarzik@pobox.com> 1124773419 -0400

[PATCH] Fix HD activity LED with ahci

Patch: fix wrong HD activity control by ahci driver

The ahci driver 1.0 sets the SActive bit on every transaction,
causing the LED to light up. The SActive bit is used only for
native command queuing (NCQ) which the current driver version
doesn't implement. Resetting the SActive bit is the device's
responsibility (by sending a "Set Device Bits FIS" to the
host adapter) but this is not required in response to
non-NCQ commands, and (most) devices don't. Thus the LED
stays always on. This patch fixes the LED behavior.

Spec references:
http://www.intel.com/technology/serialata/pdf/rev1_1.pdf, sec. 3.3.13, 5.5.1
http://www.serialata.org/docs/serialata10a.pdf
http://www.intel.com/design/storage/papers/25266401.pdf

Signed-off-by: Martin.Wilck@fujitsu-siemens.com
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>