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50 lines
2 KiB
Diff
50 lines
2 KiB
Diff
From b1d72d244e0bd8c94e52a42dcd8119ae2bfd8e1c Mon Sep 17 00:00:00 2001
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From: Maxime Ripard <maxime@cerno.tech>
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Date: Tue, 11 May 2021 17:05:11 +0200
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Subject: [PATCH 550/552] drm/vc4: hdmi: Remove the DDC probing for status
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detection
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Commit 9d44abbbb8d5 ("drm/vc4: Fall back to using an EDID probe in the
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absence of a GPIO.") added some code to read the EDID through DDC in the
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HDMI driver detect hook since the Pi3 had no HPD GPIO back then.
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However, commit b1b8f45b3130 ("ARM: dts: bcm2837: Add missing GPIOs of
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Expander") changed that a couple of years later.
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This causes an issue though since some TV (like the LG 55C8) when it
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comes out of standy will deassert the HPD line, but the EDID will
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remain readable.
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It causes an issues nn platforms without an HPD GPIO, like the Pi4,
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where the DDC probing will be our primary mean to detect a display, and
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thus we will never detect the HPD pulse. This was fine before since the
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pulse was small enough that we would never detect it, and we also didn't
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have anything (like the scrambler) that needed to be set up in the
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display.
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However, now that we have both, the display during the HPD pulse will
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clear its scrambler status, and since we won't detect the
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disconnect/reconnect cycle we will never enable the scrambler back.
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As our main reason for that DDC probing is gone, let's just remove it.
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Signed-off-by: Maxime Ripard <maxime@cerno.tech>
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---
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drivers/gpu/drm/vc4/vc4_hdmi.c | 2 --
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1 file changed, 2 deletions(-)
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diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
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index 3838606072ca..aeb1e4b23310 100644
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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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@@ -182,8 +182,6 @@ vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
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if (vc4_hdmi->hpd_gpio &&
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gpiod_get_value_cansleep(vc4_hdmi->hpd_gpio)) {
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connected = true;
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- } else if (drm_probe_ddc(vc4_hdmi->ddc)) {
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- connected = true;
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} else if (HDMI_READ(HDMI_HOTPLUG) & VC4_HDMI_HOTPLUG_CONNECTED) {
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connected = true;
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}
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--
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2.33.0
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