From 427c6bd8835e197693e9b4aedbe45c2c3c84cdce Mon Sep 17 00:00:00 2001 From: Dom Cobley Date: Wed, 1 Jun 2022 15:43:51 +0100 Subject: [PATCH] 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(-) diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 7bcba4f1ee1c..de527c9a0743 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -39,6 +39,8 @@ #include #include #include +#include +#include #include #include #include @@ -111,6 +113,10 @@ #define CEC_CLOCK_FREQ 40000 #define HDMI_14_MAX_TMDS_CLK (340 * 1000 * 1000) +/* bit field to force hotplug detection. bit0 = HDMI0 */ +static int force_hotplug = 0; +module_param(force_hotplug, int, 0644); + static const char * const output_format_str[] = { [VC4_HDMI_OUTPUT_RGB] = "RGB", [VC4_HDMI_OUTPUT_YUV420] = "YUV 4:2:0", @@ -247,7 +253,9 @@ vc4_hdmi_connector_detect(struct drm_connector *connector, bool force) WARN_ON(pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev)); - if (vc4_hdmi->hpd_gpio) { + if (force_hotplug & BIT(vc4_hdmi->encoder.base.type - VC4_ENCODER_TYPE_HDMI0)) + connected = true; + else if (vc4_hdmi->hpd_gpio) { if (gpio_get_value_cansleep(vc4_hdmi->hpd_gpio) ^ vc4_hdmi->hpd_active_low) connected = true;