From 71d796eedb3dfad70417a63e886a0b62e976fa7c Mon Sep 17 00:00:00 2001 From: Dom Cobley Date: Wed, 1 Jun 2022 15:43:51 +0100 Subject: [PATCH 649/697] drm/vc4_hdmi: Allow hotplug detect to be forced See: https://forum.libreelec.tv/thread/24783-tv-avr-turns-back-on-right-after-turning-them-off While the kernel provides a :D flag for assuming device is connected, it doesn't stop this function from being called and generating a cec_phys_addr_invalidate message when hotplug is deasserted. That message provokes a flurry of CEC messages which for many users results in the TV switching back on again and it's very hard to get it to stay switched off. It seems to only occur with an AVR and TV connected but has been observed across a number of manufacturers. The issue started with https://github.com/raspberrypi/linux/pull/4371 and this provides an optional way of getting back the old behaviour Signed-off-by: Dom Cobley --- drivers/gpu/drm/vc4/vc4_hdmi.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -43,6 +43,8 @@ #include #include #include +#include +#include #include #include #include @@ -112,6 +114,10 @@ #define HDMI_14_MAX_TMDS_CLK (340 * 1000 * 1000) +/* bit field to force hotplug detection. bit0 = HDMI0 */ +static int force_hotplug; +module_param(force_hotplug, int, 0644); + static bool vc4_hdmi_supports_scrambling(struct vc4_hdmi *vc4_hdmi) { struct drm_display_info *display = &vc4_hdmi->connector.display_info; @@ -466,7 +472,9 @@ static int vc4_hdmi_connector_detect_ctx return connector_status_unknown; } - if (vc4_hdmi->hpd_gpio) { + if (force_hotplug & BIT(vc4_hdmi->encoder.type - VC4_ENCODER_TYPE_HDMI0)) + status = connector_status_connected; + else if (vc4_hdmi->hpd_gpio) { if (gpiod_get_value_cansleep(vc4_hdmi->hpd_gpio)) status = connector_status_connected; } else {