video: tegra: dc: fix hdmi mode filter

If there are more than one hdmi modes that have same xres,
yres, and vmode, tegra_dc_hdmi_mode_equal can return true even
though pixclocks are way different from each other.
Now, tegra_dc_hdmi_mode_equal will retun false if pixclock has
more than 1Hz of difference. Also, tegra_fb_set_par will use
fb_find_nearest_mode instead of fb_find_best_mode to take
refresh rate into the consideration.

Bug: 815409

Reviewed-on: http://git-master/r/36464
(cherry picked from commit 8cf6e47dd3d4efaa3a1f0a15f1bd36ad34d3a951)

Change-Id: I14fbfba832bd130c7f04369b360d48fbbfad3d7b
Signed-off-by: Sanjay Singh Rawat <srawat@nvidia.com>
Reviewed-on: http://git-master/r/43655
Reviewed-by: Manish Tuteja <mtuteja@nvidia.com>
Tested-by: Manish Tuteja <mtuteja@nvidia.com>

2 files changed, 23 insertions, 5 deletions

diff --git a/drivers/video/tegra/dc/hdmi.c b/drivers/video/tegra/dc/hdmi.c
index c93b3c4c72f1..871560f95e40 100644
--- a/drivers/video/tegra/dc/hdmi.c
+++ b/drivers/video/tegra/dc/hdmi.c
@@ -488,11 +488,23 @@ static void hdmi_dumpregs(struct tegra_dc_hdmi_data *hdmi)
 
 #define PIXCLOCK_TOLERANCE	200
 
+static int tegra_dc_calc_clock_per_frame(const struct fb_videomode *mode)
+{
+	return (mode->left_margin + mode->xres +
+		mode->right_margin + mode->hsync_len) *
+	       (mode->upper_margin + mode->yres +
+		mode->lower_margin + mode->vsync_len);
+}
 static bool tegra_dc_hdmi_mode_equal(const struct fb_videomode *mode1,
 					const struct fb_videomode *mode2)
 {
+	int clock_per_frame = tegra_dc_calc_clock_per_frame(mode1);
+
+	/* allows up to 1Hz of pixclock difference */
 	return mode1->xres	== mode2->xres &&
 		mode1->yres	== mode2->yres &&
+		(abs(PICOS2KHZ(mode1->pixclock - mode2->pixclock)) *
+		1000 / clock_per_frame <= 1) &&
 		mode1->vmode	== mode2->vmode;
 }
 
@@ -512,16 +524,19 @@ static bool tegra_dc_hdmi_mode_filter(const struct tegra_dc *dc,
 					struct fb_videomode *mode)
 {
 	int i;
-	int clocks;
+	int clock_per_frame;
+
+	if (!mode->pixclock)
+		return false;
 
 	for (i = 0; i < ARRAY_SIZE(tegra_dc_hdmi_supported_modes); i++) {
 		if (tegra_dc_hdmi_mode_equal(&tegra_dc_hdmi_supported_modes[i], mode) &&
 			tegra_dc_hdmi_valid_pixclock(dc, &tegra_dc_hdmi_supported_modes[i])) {
 			memcpy(mode, &tegra_dc_hdmi_supported_modes[i], sizeof(*mode));
 			mode->flag = FB_MODE_IS_DETAILED;
-			clocks = (mode->left_margin + mode->xres + mode->right_margin + mode->hsync_len) *
-				(mode->upper_margin + mode->yres + mode->lower_margin + mode->vsync_len);
-			mode->refresh = (PICOS2KHZ(mode->pixclock) * 1000) / clocks;
+			clock_per_frame = tegra_dc_calc_clock_per_frame(mode);
+			mode->refresh = (PICOS2KHZ(mode->pixclock) * 1000)
+					/ clock_per_frame;
 			return true;
 		}
 	}
diff --git a/drivers/video/tegra/fb.c b/drivers/video/tegra/fb.c
index 1b1952b774b3..1f628d51c5af 100644
--- a/drivers/video/tegra/fb.c
+++ b/drivers/video/tegra/fb.c
@@ -175,9 +175,12 @@ static int tegra_fb_set_par(struct fb_info *info)
 
 	if (var->pixclock) {
 		struct tegra_dc_mode mode;
+		struct fb_videomode m;
+
+		fb_var_to_videomode(&m, var);
 
 		info->mode = (struct fb_videomode *)
-			fb_find_best_mode(var, &info->modelist);
+			fb_find_nearest_mode(&m, &info->modelist);
 		if (!info->mode) {
 			dev_warn(&tegra_fb->ndev->dev, "can't match video mode\n");
 			return -EINVAL;