47 lines
1.7 KiB
Diff
47 lines
1.7 KiB
Diff
From 37b204f22778f51cad7bdf678d7574ff6d7508a6 Mon Sep 17 00:00:00 2001
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From: Dave Stevenson <dave.stevenson@raspberrypi.com>
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Date: Wed, 25 Mar 2020 18:22:40 +0000
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Subject: [PATCH] drm/vc4: Alter the HDMI state machine clock calc to
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allow for 1920x1200
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Whilst the documentation for BCM2835 states that the HDMI state machine
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clock needs to be 108% of the pixel clock, other documentation says
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that it only has to be greater than the pixel clock. The firmware
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uses 101%, and that allows 1920x1200@60Hz to work within the
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constraint of the HSM clock being < 163.68MHz.
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Adopt 101%, and increase the maximum pixel clock for vc4 to 162MHz
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so that it too supports 1920x1200@60.
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Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
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---
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drivers/gpu/drm/vc4/vc4_hdmi.c | 9 +++++----
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1 file changed, 5 insertions(+), 4 deletions(-)
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--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
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+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
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@@ -581,10 +581,11 @@ static void vc4_hdmi_encoder_enable(stru
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}
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/*
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- * The HSM rate needs to be at 108% of the pixel clock, with a
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- * minimum of 108MHz.
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+ * The HSM rate needs to be slightly greater than the pixel clock, with
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+ * a minimum of 108MHz.
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+ * Use 101% as this is what the firmware uses.
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*/
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- hsm_rate = max_t(unsigned long, 108000000, (pixel_rate / 100) * 108);
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+ hsm_rate = max_t(unsigned long, 108000000, (pixel_rate / 100) * 101);
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ret = clk_set_rate(vc4_hdmi->hsm_clock, hsm_rate);
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if (ret) {
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DRM_ERROR("Failed to set HSM clock rate: %d\n", ret);
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@@ -1731,7 +1732,7 @@ static int vc4_hdmi_dev_remove(struct pl
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}
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static const struct vc4_hdmi_variant bcm2835_variant = {
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- .max_pixel_clock = 148500000,
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+ .max_pixel_clock = 162000000,
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.audio_available = true,
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.cec_available = true,
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.registers = vc4_hdmi_fields,
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