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From: Alessio Belle <alessio.belle@imgtec.com>
To: Frank Binns <frank.binns@imgtec.com>,
	Matt Coster <matt.coster@imgtec.com>,
	Brajesh Gupta <brajesh.gupta@imgtec.com>,
	"Alexandru Dadu" <alexandru.dadu@imgtec.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>
Cc: <dri-devel@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>,
	<stable@vger.kernel.org>,
	Alessio Belle <alessio.belle@imgtec.com>
Subject: [PATCH] drm/imagination: Fix deadlock in soft reset sequence
Date: Mon, 9 Mar 2026 15:23:48 +0000	[thread overview]
Message-ID: <20260309-fix-soft-reset-v1-1-121113be554f@imgtec.com> (raw)

The soft reset sequence is currently executed from the threaded IRQ
handler, hence it cannot call disable_irq() which internally waits
for IRQ handlers, i.e. itself, to complete.

Use disable_irq_nosync() during a soft reset instead.

Fixes: cc1aeedb98ad ("drm/imagination: Implement firmware infrastructure and META FW support")
Cc: stable@vger.kernel.org
Signed-off-by: Alessio Belle <alessio.belle@imgtec.com>
---
 drivers/gpu/drm/imagination/pvr_power.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/imagination/pvr_power.c b/drivers/gpu/drm/imagination/pvr_power.c
index 7a8765c0c1ed..046cce76498a 100644
--- a/drivers/gpu/drm/imagination/pvr_power.c
+++ b/drivers/gpu/drm/imagination/pvr_power.c
@@ -510,7 +510,16 @@ pvr_power_reset(struct pvr_device *pvr_dev, bool hard_reset)
 	}
 
 	/* Disable IRQs for the duration of the reset. */
-	disable_irq(pvr_dev->irq);
+	if (hard_reset) {
+		disable_irq(pvr_dev->irq);
+	} else {
+		/*
+		 * Soft reset is triggered as a response to a FW command to the Host and is
+		 * processed from the threaded IRQ handler. This code cannot (nor needs to)
+		 * wait for any IRQ processing to complete.
+		 */
+		disable_irq_nosync(pvr_dev->irq);
+	}
 
 	do {
 		if (hard_reset) {

---
base-commit: d2e20c8951e4bb5f4a828aed39813599980353b6
change-id: 20260309-fix-soft-reset-8f32c3783d3d

Best regards,
-- 
Alessio Belle <alessio.belle@imgtec.com>


             reply	other threads:[~2026-03-09 15:24 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-09 15:23 Alessio Belle [this message]
2026-03-10  2:12 ` Claude review: drm/imagination: Fix deadlock in soft reset sequence Claude Code Review Bot
2026-03-10  2:12 ` Claude Code Review Bot

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