drm/i915/cnl: Fix loadgen select programming on ddi vswing sequence

The condition for setting the Loadgen Select bit of
PORT_TX_DW4 register during DDI Vswing Sequence should be
Bit rate <=6 GHz whereas the existing code checks only
Bit Rate < 6GHz. This patch fixes this condition.
While at it also remove the redundant paranthesis.

Fixes: cf54ca8bc567 ("drm/i915/cnl: Implement voltage swing sequence.")
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1500329122-32662-1-git-send-email-manasi.d.navare@intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit a8e45a1c42d11597e975f3e5f2fe182f90cdaa7f)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 80e96f1f49d2d09deb59ec08e6ebe78ac07b8cf3..9edeaaef77adf6c38e23733769e271147698f02a 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1896,8 +1896,8 @@ static void cnl_ddi_vswing_sequence(struct intel_encoder *encoder, u32 level)
                val = I915_READ(CNL_PORT_TX_DW4_LN(port, ln));
                val &= ~LOADGEN_SELECT;
 
-               if (((rate < 600000) && (width == 4) && (ln >= 1))  ||
-                   ((rate < 600000) && (width < 4) && ((ln == 1) || (ln == 2)))) {
+               if ((rate <= 600000 && width == 4 && ln >= 1)  ||
+                   (rate <= 600000 && width < 4 && (ln == 1 || ln == 2))) {
                        val |= LOADGEN_SELECT;
                }
                I915_WRITE(CNL_PORT_TX_DW4_LN(port, ln), val);