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    SubjectRe: [PATCH][drivers/misc/thinkpad_acpi.c] duplicate test if (level & TP_EC_FAN_FULLSPEED)
    Henrique de Moraes Holschuh wrote:
    > On Tue, 05 Feb 2008, Roel Kluin wrote:
    >> 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))
    >
    > ACK. This needs to be sent to stable as well. I think both 2.6.22 and
    > 2.6.23 need this patch.
    >

    CC stable@kernel.org


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