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36 lines
1.4 KiB
36 lines
1.4 KiB
6 years ago
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From 7f98947db09ad419ca73082230ade1f29f18bd82 Mon Sep 17 00:00:00 2001
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From: Eric Anholt <eric@anholt.net>
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Date: Mon, 6 Mar 2017 12:17:16 -0800
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Subject: [PATCH 128/454] panel-raspberrypi-touchscreen: Round up clk rate to
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fix DSI panel.
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Commit 488f9bc8e3def93e0baef53cee2026c2cb0d8956 slightly increased the
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reported rate of PLLD, so the clk driver decided that PLLD/3/8 was now
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higher than our requested pixel clock rate and rejected it in favor of
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PLLD/4/8, which then ran the pixel clock way out of spec.
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By bumping the requested clock rate just slightly, we get back to
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PLLD/3/8 like we wanted and the panel displays content again.
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Signed-off-by: Eric Anholt <eric@anholt.net>
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---
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drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c | 7 ++++++-
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1 file changed, 6 insertions(+), 1 deletion(-)
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--- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
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+++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
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@@ -220,7 +220,12 @@ static const struct drm_display_mode rpi
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#define HBP 46
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#define HFP ((PIXEL_CLOCK / (VTOTAL * VREFRESH)) - (HACT + HSW + HBP))
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- .clock = PIXEL_CLOCK / 1000,
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+ /* Round up the pixel clock a bit (10khz), so that the
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+ * "don't run things faster than the requested clock
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+ * rate" rule of the clk driver doesn't reject the
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+ * divide-by-3 mode due to rounding error.
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+ */
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+ .clock = PIXEL_CLOCK / 1000 + 10,
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.hdisplay = HACT,
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.hsync_start = HACT + HFP,
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.hsync_end = HACT + HFP + HSW,
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