drm/i915: Fix fast wake AUX sync len

commit e1c71f8f918047ce822dc19b42ab1261ed259fd1 upstream.

Fast wake should use 8 SYNC pulses for the preamble
and 10-16 SYNC pulses for the precharge. Reduce our
fast wake SYNC count to match the maximum value.
We also use the maximum precharge length for normal
AUX transactions.

Cc: stable@vger.kernel.org
Cc: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230329172434.18744-1-ville.syrjala@linux.intel.com
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
(cherry picked from commit 605f7c73133341d4b762cbd9a22174cc22d4c38b)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
index 664bebdecea76bb7fa3f2b4c76929fa28b505bee..d5fed2eb66d2b28e3a2e4221488b5a4415599d7f 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
@@ -166,7 +166,7 @@ static u32 skl_get_aux_send_ctl(struct intel_dp *intel_dp,
              DP_AUX_CH_CTL_TIME_OUT_MAX |
              DP_AUX_CH_CTL_RECEIVE_ERROR |
              (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
-             DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(32) |
+             DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(24) |
              DP_AUX_CH_CTL_SYNC_PULSE_SKL(32);
 
        if (intel_tc_port_in_tbt_alt_mode(dig_port))