Attachment 119299 Details for Bug 92217 – [PATCH] drm/edid: Make the detailed timing CEA/HDMI mode fixup accept up to 5kHz clock difference

[patch] [PATCH] drm/edid: Make the detailed timing CEA/HDMI mode fixup accept up to 5kHz clock difference

0001-drm-edid-Make-the-detailed-timing-CEA-HDMI-mode-fixu.patch (text/plain), 6.19 KB, created by Ville Syrjala on 2015-10-30 13:42:51 UTC

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Creator: Ville Syrjala

Created: 2015-10-30 13:42:51 UTC

Size: 6.19 KB

patch

obsolete

>From a6d3c5181d7636d4b7270656e666a0aa822c94be Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
>Date: Fri, 30 Oct 2015 02:28:36 +0200
>Subject: [PATCH] drm/edid: Make the detailed timing CEA/HDMI mode fixup accept
> up to 5kHz clock difference
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>Rather than using drm_match_cea_mode() to see if the EDID detailed
>timings are supposed to represent one of the CEA/HDMI modes, add a
>special version of that function that takes in an explicit clock
>tolerance value (in kHz). When looking at the detailed timings specify
>the tolerance as 5kHz due to the 10kHz clock resolution limit inherent
>in detailed timings.
>
>drm_match_cea_mode() uses the normal KHZ2PICOS() matching of clocks,
>which only allows smaller errors for lower clocks (eg. for 25200 it
>won't allow any error) and a bigger error for higher clocks (eg. for
>297000 it actually matches 296913-297000). So it doesn't reallt match
>what we want for the fixup. Using the explicit +-5kHz is much better
>for this use case.
>
>Not sure if we should change the normal mode matching to also use
>something else besides KHZ2PICOS() since it allows a different
>proportion of error depending on the clock. I believe VESA CVT
>allows a maximum deviation of .5%, so using that for normal mode
>matching might be a good idea?
>
>Cc: Adam Jackson <ajax@redhat.com>
>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92217
>Signed-off-by: Ville SyrjÃ¤lÃ¤ <ville.syrjala@linux.intel.com>
>---
> drivers/gpu/drm/drm_edid.c  | 60 +++++++++++++++++++++++++++++++++++++++++++--
> drivers/gpu/drm/drm_modes.c | 19 +++++++++++++-
> include/drm/drm_modes.h     |  2 ++
> 3 files changed, 78 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>index d5d2c03..47d4a08 100644
>--- a/drivers/gpu/drm/drm_edid.c
>+++ b/drivers/gpu/drm/drm_edid.c
>@@ -2545,6 +2545,32 @@ cea_mode_alternate_clock(const struct drm_display_mode *cea_mode)
> 	return clock;
> }
> 
>+static u8 drm_match_cea_mode_clock_tolerance(const struct drm_display_mode *to_match,
>+					     unsigned int clock_tolerance)
>+{
>+	u8 mode;
>+
>+	if (!to_match->clock)
>+		return 0;
>+
>+	for (mode = 0; mode < ARRAY_SIZE(edid_cea_modes); mode++) {
>+		const struct drm_display_mode *cea_mode = &edid_cea_modes[mode];
>+		unsigned int clock1, clock2;
>+
>+		/* Check both 60Hz and 59.94Hz */
>+		clock1 = cea_mode->clock;
>+		clock2 = cea_mode_alternate_clock(cea_mode);
>+
>+		if (abs(to_match->clock - clock1) > clock_tolerance &&
>+		    abs(to_match->clock - clock2) > clock_tolerance)
>+			continue;
>+
>+		if (drm_mode_equal_no_clocks(to_match, cea_mode))
>+			return mode + 1;
>+	}
>+	return 0;
>+}
>+
> /**
>  * drm_match_cea_mode - look for a CEA mode matching given mode
>  * @to_match: display mode
>@@ -2609,6 +2635,32 @@ hdmi_mode_alternate_clock(const struct drm_display_mode *hdmi_mode)
> 	return cea_mode_alternate_clock(hdmi_mode);
> }
> 
>+static u8 drm_match_hdmi_mode_clock_tolerance(const struct drm_display_mode *to_match,
>+					      unsigned int clock_tolerance)
>+{
>+	u8 mode;
>+
>+	if (!to_match->clock)
>+		return 0;
>+
>+	for (mode = 0; mode < ARRAY_SIZE(edid_4k_modes); mode++) {
>+		const struct drm_display_mode *hdmi_mode = &edid_4k_modes[mode];
>+		unsigned int clock1, clock2;
>+
>+		/* Make sure to also match alternate clocks */
>+		clock1 = hdmi_mode->clock;
>+		clock2 = hdmi_mode_alternate_clock(hdmi_mode);
>+
>+		if (abs(to_match->clock - clock1) > clock_tolerance &&
>+		    abs(to_match->clock - clock2) > clock_tolerance)
>+			continue;
>+
>+		if (drm_mode_equal_no_clocks(to_match, hdmi_mode))
>+			return mode + 1;
>+	}
>+	return 0;
>+}
>+
> /*
>  * drm_match_hdmi_mode - look for a HDMI mode matching given mode
>  * @to_match: display mode
>@@ -3119,14 +3171,18 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode)
> 	u8 mode_idx;
> 	const char *type;
> 
>-	mode_idx = drm_match_cea_mode(mode) - 1;
>+	/*
>+	 * allow 5kHz clock difference either way to account for
>+	 * the 10kHz clock resolution limit of detailed timings.
>+	 */
>+	mode_idx = drm_match_cea_mode_clock_tolerance(mode, 5) - 1;
> 	if (mode_idx < ARRAY_SIZE(edid_cea_modes)) {
> 		type = "CEA";
> 		cea_mode = &edid_cea_modes[mode_idx];
> 		clock1 = cea_mode->clock;
> 		clock2 = cea_mode_alternate_clock(cea_mode);
> 	} else {
>-		mode_idx = drm_match_hdmi_mode(mode) - 1;
>+		mode_idx = drm_match_hdmi_mode_clock_tolerance(mode, 5) - 1;
> 		if (mode_idx < ARRAY_SIZE(edid_4k_modes)) {
> 			type = "HDMI";
> 			cea_mode = &edid_4k_modes[mode_idx];
>diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
>index 9480464..4d2a241 100644
>--- a/drivers/gpu/drm/drm_modes.c
>+++ b/drivers/gpu/drm/drm_modes.c
>@@ -917,13 +917,30 @@ bool drm_mode_equal(const struct drm_display_mode *mode1, const struct drm_displ
> 	} else if (mode1->clock != mode2->clock)
> 		return false;
> 
>+	return drm_mode_equal_no_clocks(mode1, mode2);
>+}
>+EXPORT_SYMBOL(drm_mode_equal);
>+
>+/**
>+ * drm_mode_equal_no_clocks - test modes for equality
>+ * @mode1: first mode
>+ * @mode2: second mode
>+ *
>+ * Check to see if @mode1 and @mode2 are equivalent, but
>+ * don't check the pixel clocks.
>+ *
>+ * Returns:
>+ * True if the modes are equal, false otherwise.
>+ */
>+bool drm_mode_equal_no_clocks(const struct drm_display_mode *mode1, const struct drm_display_mode *mode2)
>+{
> 	if ((mode1->flags & DRM_MODE_FLAG_3D_MASK) !=
> 	    (mode2->flags & DRM_MODE_FLAG_3D_MASK))
> 		return false;
> 
> 	return drm_mode_equal_no_clocks_no_stereo(mode1, mode2);
> }
>-EXPORT_SYMBOL(drm_mode_equal);
>+EXPORT_SYMBOL(drm_mode_equal_no_clocks);
> 
> /**
>  * drm_mode_equal_no_clocks_no_stereo - test modes for equality
>diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
>index 08a8cac..f9115ae 100644
>--- a/include/drm/drm_modes.h
>+++ b/include/drm/drm_modes.h
>@@ -222,6 +222,8 @@ struct drm_display_mode *drm_mode_duplicate(struct drm_device *dev,
> 					    const struct drm_display_mode *mode);
> bool drm_mode_equal(const struct drm_display_mode *mode1,
> 		    const struct drm_display_mode *mode2);
>+bool drm_mode_equal_no_clocks(const struct drm_display_mode *mode1,
>+			      const struct drm_display_mode *mode2);
> bool drm_mode_equal_no_clocks_no_stereo(const struct drm_display_mode *mode1,
> 					const struct drm_display_mode *mode2);
> 
>-- 
>2.4.10
>

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