[PATCH][drivers/misc/thinkpad_acpi.c] duplicate test if (level & TP_EC_FAN_FULLSPEED)

Roel Kluin
2008-02-04T23:25:54Z

Roland Dreier wrote:
> > /* safety net should the EC not support AUTO
> > * or FULLSPEED mode bits and just ignore them */
> > if (level & TP_EC_FAN_FULLSPEED)
> > level |= 7; /* safety min speed 7 */
> > else if (level & TP_EC_FAN_FULLSPEED)
> > level |= 4; /* safety min speed 4 */
> >
> > Note the duplicate test 'if (level & TP_EC_FAN_FULLSPEED)'. should
> > this be replaced by
>
> Actually I suspect one of the two tests should be against TP_EC_FAN_AUTO
> (based on the comment).
>

Thanks Roland, for your info

based on the comments in commit eaa7571b2d1a08873e4bdd8e6db3431df61cd9ad,
I think this should be modified like below:

ACPI: thinkpad-acpi: add a safety net for TPEC fan control mode
The Linux ThinkPad community is not positive that all ThinkPads that do
HFSP EC fan control do implement full-speed and auto modes, some of the
earlier ones supporting HFSP might not.

If the EC ignores the AUTO or FULL-SPEED bits, it will pay attention to the
lower three bits that set the fan level. And as thinkpad-acpi was leaving
these set to zero, it would stop(!) the fan, which is Not A Good Thing.
So, as a safety net, we now make sure to also set the fan level part of the
HFSP register to speed 7 for full-speed, and a minimum of speed 4 for auto
mode.
--
second TP_EC_FAN_FULLSPEED should be P_EC_FAN_AUTO

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
---
diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index cf56647..3c323fe 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -4138,7 +4138,7 @@ static int fan_set_level(int level)
* or FULLSPEED mode bits and just ignore them */
if (level & TP_EC_FAN_FULLSPEED)
level |= 7; /* safety min speed 7 */
- else if (level & TP_EC_FAN_FULLSPEED)
+ else if (level & TP_EC_FAN_AUTO)
level |= 4; /* safety min speed 4 */

if (!acpi_ec_write(fan_status_offset, level))