linux-kernel - [PATCH 5.18 0396/1095] drm/vc4: hdmi: Switch to pm_runtime_status

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Date:   Mon, 15 Aug 2022 19:56:35 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Maxime Ripard <maxime@...no.tech>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.18 0396/1095] drm/vc4: hdmi: Switch to pm_runtime_status_suspended

From: Dave Stevenson <dave.stevenson@...pberrypi.com>

[ Upstream commit fcef97e70094a33ded73b3eb9bef06698c6e9c12 ]

If the controller isn't clocked or its domain powered up, the register
accesses will either stall the CPU or return garbage, respectively.

Thus, we had a warning in our register access function to complain when
that kind of risky accesses were performed.

In order to check the runtime_pm power state, we were using
pm_runtime_active(), but it turns out that it will become active only
once the runtime_resume hook has been executed.

This prevents us from doing any WARN-free register access in our
runtime_resume() implementation, while this is valid.

Let's switch to pm_runtime_status_suspended() instead.

Fixes: 14e193b95604 ("drm/vc4: hdmi: Warn if we access the controller while disabled")
Signed-off-by: Dave Stevenson <dave.stevenson@...pberrypi.com>
Link: https://lore.kernel.org/r/20220613144800.326124-23-maxime@cerno.tech
Signed-off-by: Maxime Ripard <maxime@...no.tech>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/vc4/vc4_hdmi_regs.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi_regs.h b/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
index 24056441a4bb..72b769412482 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
@@ -417,7 +417,7 @@ static inline u32 vc4_hdmi_read(struct vc4_hdmi *hdmi,
 	const struct vc4_hdmi_variant *variant = hdmi->variant;
 	void __iomem *base;
 
-	WARN_ON(!pm_runtime_active(&hdmi->pdev->dev));
+	WARN_ON(pm_runtime_status_suspended(&hdmi->pdev->dev));
 
 	if (reg >= variant->num_registers) {
 		dev_warn(&hdmi->pdev->dev,
@@ -447,7 +447,7 @@ static inline void vc4_hdmi_write(struct vc4_hdmi *hdmi,
 
 	lockdep_assert_held(&hdmi->hw_lock);
 
-	WARN_ON(!pm_runtime_active(&hdmi->pdev->dev));
+	WARN_ON(pm_runtime_status_suspended(&hdmi->pdev->dev));
 
 	if (reg >= variant->num_registers) {
 		dev_warn(&hdmi->pdev->dev,
-- 
2.35.1