ACPI: thinkpad-acpi: add a safety net for TPEC fan control mode (eaa7571b) · Commits · 戴 / test

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@hmh.eng.br> Signed-off-by:

Len Brown <len.brown@intel.com>

drivers/misc/thinkpad_acpi.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -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;

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