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31 lines
946 B
Diff
31 lines
946 B
Diff
From 9da2d153eb010d3e92083c322e87de9ae066d93e Mon Sep 17 00:00:00 2001
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From: popcornmix <popcornmix@gmail.com>
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Date: Thu, 2 Apr 2020 16:46:31 +0100
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Subject: [PATCH] vc4_hdmi_phy: Fix offset calculation
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The original firmware code worked with float and did
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offset = ((vco_freq / fref * 2) * (1 << 22));
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offset >>= 2;
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In this code it's all integer so doing the integer divide before the shift loses lots of precision
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This fixes the issue of 1080p59.94 mode having 59.64 fps
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Signed-off-by: popcornmix <popcornmix@gmail.com>
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---
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drivers/gpu/drm/vc4/vc4_hdmi_phy.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/drivers/gpu/drm/vc4/vc4_hdmi_phy.c
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+++ b/drivers/gpu/drm/vc4/vc4_hdmi_phy.c
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@@ -192,8 +192,8 @@ static u32 phy_get_rm_offset(unsigned lo
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/* RM offset is stored as 9.22 format */
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offset = vco_freq * 2;
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- do_div(offset, fref);
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offset = offset << 22;
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+ do_div(offset, fref);
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offset >>= 2;
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return offset;
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