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20ea6adbf1
Build system: x86_64 Build-tested: bcm2708, bcm2709, bcm2710, bcm2711 Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B Signed-off-by: Marty Jones <mj8263788@gmail.com> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
48 lines
2.0 KiB
Diff
48 lines
2.0 KiB
Diff
From faa24f47c0066893e0b7772befe378bde4dc2ff9 Mon Sep 17 00:00:00 2001
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From: Maxime Ripard <maxime@cerno.tech>
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Date: Mon, 25 Oct 2021 17:28:54 +0200
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Subject: [PATCH] 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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Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
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Link: https://lore.kernel.org/r/20211025152903.1088803-2-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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--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
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+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
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@@ -175,8 +175,6 @@ vc4_hdmi_connector_detect(struct drm_con
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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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