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.
Signed-off-by: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx>
---
drivers/misc/thinkpad_acpi.c | 16 ++++++++++++----
1 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index a4d7ee4..79abc68 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -3185,6 +3185,13 @@ static int fan_set_level(int level)
((level < 0) || (level > 7)))
return -EINVAL;
+ /* 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 */
+
if (!acpi_ec_write(fan_status_offset, level))
return -EIO;
else
@@ -3233,8 +3240,10 @@ static int fan_set_enable(void)
break;
/* Don't go out of emergency fan mode */
- if (s != 7)
- s = TP_EC_FAN_AUTO;
+ if (s != 7) {
+ s &= 0x07;
+ s |= TP_EC_FAN_AUTO | 4; /* min fan speed 4 */
+ }
if (!acpi_ec_write(fan_status_offset, s))
rc = -EIO;
@@ -3252,8 +3261,7 @@ static int fan_set_enable(void)
s &= 0x07;
/* Set fan to at least level 4 */
- if (s < 4)
- s = 4;
+ s |= 4;
if (!acpi_evalf(sfan_handle, NULL, NULL, "vd", s))
rc= -EIO;
--
1.5.1
-
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