linux-kernel - [PATCH 1/2] drm/rockchip: dw_hdmi_qp: Fix RK3576 HPD interrupt handling

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Message-Id: <20260115-dw-hdmi-qp-hpd-v1-1-e59c166eaa65@collabora.com>
Date: Thu, 15 Jan 2026 18:24:43 +0200
From: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
To: Sandy Huang <hjc@...k-chips.com>, 
 Heiko Stübner <heiko@...ech.de>, 
 Andy Yan <andy.yan@...k-chips.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Cc: kernel@...labora.com, dri-devel@...ts.freedesktop.org, 
 linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, 
 linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] drm/rockchip: dw_hdmi_qp: Fix RK3576 HPD interrupt
 handling

The threaded interrupt handler on RK3576 checks HPD IRQ status before
deciding to continue with interrupt clearing and unmasking.

This is not only redundant, since a similar verification has been
already performed by the hard IRQ handler before masking the interrupt,
but is also error prone, because it might happen that hardware clears
the status register right after the masking operation completes, and
before the threaded handler reads its value.

The consequence is that HPD IRQ gets never unmasked, which breaks
hotplug detection until reloading the driver or rebooting the system.

Drop the unnecessary verification of the HPD interrupt status from the
threaded interrupt handler.

Fixes: 36439120efbd ("drm/rockchip: dw_hdmi_qp: Add basic RK3576 HDMI output support")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
---
 drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
index c4365909c3e7..33b0f032258a 100644
--- a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
@@ -280,12 +280,7 @@ static irqreturn_t dw_hdmi_qp_rk3576_hardirq(int irq, void *dev_id)
 static irqreturn_t dw_hdmi_qp_rk3576_irq(int irq, void *dev_id)
 {
 	struct rockchip_hdmi_qp *hdmi = dev_id;
-	u32 intr_stat, val;
-
-	regmap_read(hdmi->regmap, RK3576_IOC_HDMI_HPD_STATUS, &intr_stat);
-
-	if (!intr_stat)
-		return IRQ_NONE;
+	u32 val;
 
 	val = FIELD_PREP_WM16(RK3576_HDMI_HPD_INT_CLR, 1);
 	regmap_write(hdmi->regmap, RK3576_IOC_MISC_CON0, val);

-- 
2.52.0