linux-kernel - [PATCH] drm/bridge: adv7511: Exit interrupt handling when necessary

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Date: Thu, 16 May 2024 18:10:06 +0800
From: Liu Ying <victor.liu@....com>
To: dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Cc: andrzej.hajda@...el.com,
	neil.armstrong@...aro.org,
	rfoss@...nel.org,
	Laurent.pinchart@...asonboard.com,
	jonas@...boo.se,
	jernej.skrabec@...il.com,
	maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org,
	tzimmermann@...e.de,
	airlied@...il.com,
	daniel@...ll.ch,
	biju.das.jz@...renesas.com,
	dmitry.baryshkov@...aro.org,
	u.kleine-koenig@...gutronix.de,
	aford173@...il.com,
	jani.nikula@...el.com,
	bli@...g-olufsen.dk,
	sui.jingfeng@...ux.dev
Subject: [PATCH] drm/bridge: adv7511: Exit interrupt handling when necessary

Commit f3d9683346d6 ("drm/bridge: adv7511: Allow IRQ to share GPIO pins")
fails to consider the case where adv7511->i2c_main->irq is zero, i.e.,
no interrupt requested at all.

Without interrupt, adv7511_wait_for_edid() could return -EIO sometimes,
because it polls adv7511->edid_read flag by calling adv7511_irq_process()
a few times, but adv7511_irq_process() happens to refuse to handle
interrupt by returning -ENODATA.  Hence, EDID retrieval fails randomly.

Fix the issue by checking adv7511->i2c_main->irq before exiting interrupt
handling from adv7511_irq_process().

Fixes: f3d9683346d6 ("drm/bridge: adv7511: Allow IRQ to share GPIO pins")
Signed-off-by: Liu Ying <victor.liu@....com>
---
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index 6089b0bb9321..2074fa3c1b7b 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -479,7 +479,8 @@ static int adv7511_irq_process(struct adv7511 *adv7511, bool process_hpd)
 		return ret;
 
 	/* If there is no IRQ to handle, exit indicating no IRQ data */
-	if (!(irq0 & (ADV7511_INT0_HPD | ADV7511_INT0_EDID_READY)) &&
+	if (adv7511->i2c_main->irq &&
+	    !(irq0 & (ADV7511_INT0_HPD | ADV7511_INT0_EDID_READY)) &&
 	    !(irq1 & ADV7511_INT1_DDC_ERROR))
 		return -ENODATA;
 
-- 
2.37.1