[Intel-gfx] [PATCH 7/8] drm/i915: try harder to find WR PLL clock settings

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni at intel.com>

If we don't find the exact refresh rate, go with the next one. This
makes some modes work for me. They won't have the best settings, but
will at least have something. Just returning from this function when
we don't find the perfect settings does not help us at all.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 33 ++++++++++++++-------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index ff03a3a..db242cf 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -267,7 +267,8 @@ struct wrpll_tmds_clock {
 	u16 r2;		/* Reference divider */
 };
 
-/* Table of matching values for WRPLL clocks programming for each frequency */
+/* Table of matching values for WRPLL clocks programming for each frequency.
+ * The code assumes this table is sorted. */
 static const struct wrpll_tmds_clock wrpll_tmds_clock_table[] = {
 	{19750,	38,	25,	18},
 	{20000,	48,	32,	18},
@@ -658,7 +659,7 @@ void intel_ddi_mode_set(struct drm_encoder *encoder,
 	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
 	int port = intel_hdmi->ddi_port;
 	int pipe = intel_crtc->pipe;
-	int p, n2, r2, valid=0;
+	int p, n2, r2;
 	u32 temp, i;
 
 	/* On Haswell, we need to enable the clocks and prepare DDI function to
@@ -666,26 +667,20 @@ void intel_ddi_mode_set(struct drm_encoder *encoder,
 	 */
 	DRM_DEBUG_KMS("Preparing HDMI DDI mode for Haswell on port %c, pipe %c\n", port_name(port), pipe_name(pipe));
 
-	for (i=0; i < ARRAY_SIZE(wrpll_tmds_clock_table); i++) {
-		if (crtc->mode.clock == wrpll_tmds_clock_table[i].clock) {
-			p = wrpll_tmds_clock_table[i].p;
-			n2 = wrpll_tmds_clock_table[i].n2;
-			r2 = wrpll_tmds_clock_table[i].r2;
+	for (i = 0; i < ARRAY_SIZE(wrpll_tmds_clock_table); i++)
+		if (crtc->mode.clock <= wrpll_tmds_clock_table[i].clock)
+			break;
 
-			DRM_DEBUG_KMS("WR PLL clock: found settings for %dKHz refresh rate: p=%d, n2=%d, r2=%d\n",
-					crtc->mode.clock,
-					p, n2, r2);
+	if (i == ARRAY_SIZE(wrpll_tmds_clock_table))
+		i--;
 
-			valid = 1;
-			break;
-		}
-	}
+	if (wrpll_tmds_clock_table[i].clock != crtc->mode.clock)
+		DRM_INFO("WR PLL: using settings for %dKHz on %dKHz mode\n",
+			 wrpll_tmds_clock_table[i].clock, crtc->mode.clock);
 
-	if (!valid) {
-		DRM_ERROR("Unable to find WR PLL clock settings for %dKHz refresh rate\n",
-				crtc->mode.clock);
-		return;
-	}
+	p = wrpll_tmds_clock_table[i].p;
+	n2 = wrpll_tmds_clock_table[i].n2;
+	r2 = wrpll_tmds_clock_table[i].r2;
 
 	/* Enable LCPLL if disabled */
 	temp = I915_READ(LCPLL_CTL);
-- 
1.7.11.2