From fb72ae693cc973cc57de37ed7990aa9e681af6a1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Fri, 29 Oct 2021 22:18:01 +0300
Subject: drm/i915: Don't request GMBUS to generate irqs when called while irqs
 are off
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Git-commit: fa2a6c5b9cfb0dfbd1b811b154a036df1017ce66
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

We will need to do some i2c poking from the encoder->shutdown() hook.
Currently that gets called after irqs have been turned off. We still
poll the gmbus status bits even if the interrupt never arrives so
things will work just fine. But seems like asking gmbus to generate
interrupts we will never see is a bit pointless, so don't.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211029191802.18448-1-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_gmbus.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_gmbus.c b/drivers/gpu/drm/i915/display/intel_gmbus.c
index ceb1bf8a8c3c..3b8b84177085 100644
--- a/drivers/gpu/drm/i915/display/intel_gmbus.c
+++ b/drivers/gpu/drm/i915/display/intel_gmbus.c
@@ -334,6 +334,15 @@ intel_gpio_setup(struct intel_gmbus *bus, unsigned int pin)
 	algo->data = bus;
 }
 
+static bool has_gmbus_irq(struct drm_i915_private *i915)
+{
+	/*
+	 * encoder->shutdown() may want to use GMBUS
+	 * after irqs have already been disabled.
+	 */
+	return HAS_GMBUS_IRQ(i915) && intel_irqs_enabled(i915);
+}
+
 static int gmbus_wait(struct drm_i915_private *dev_priv, u32 status, u32 irq_en)
 {
 	DEFINE_WAIT(wait);
@@ -344,7 +353,7 @@ static int gmbus_wait(struct drm_i915_private *dev_priv, u32 status, u32 irq_en)
 	 * we also need to check for NAKs besides the hw ready/idle signal, we
 	 * need to wake up periodically and check that ourselves.
 	 */
-	if (!HAS_GMBUS_IRQ(dev_priv))
+	if (!has_gmbus_irq(dev_priv))
 		irq_en = 0;
 
 	add_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
@@ -375,7 +384,7 @@ gmbus_wait_idle(struct drm_i915_private *dev_priv)
 
 	/* Important: The hw handles only the first bit, so set only one! */
 	irq_enable = 0;
-	if (HAS_GMBUS_IRQ(dev_priv))
+	if (has_gmbus_irq(dev_priv))
 		irq_enable = GMBUS_IDLE_EN;
 
 	add_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
-- 
2.38.1