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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Karol Herbst <kherbst@redhat.com>,
        Thierry Reding <treding@nvidia.com>,
        Ben Skeggs <bskeggs@redhat.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 07/34] drm/nouveau/pci: do a msi rearm on init
Date:   Fri,  2 Mar 2018 09:51:03 +0100
Message-Id: <20180302084436.470546495@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Karol Herbst <kherbst@redhat.com>


[ Upstream commit a121027d2747168df0aac0c3da35509eea39f61c ]

On my GP107 when I load nouveau after unloading it, for some reason the
GPU stopped sending or the CPU stopped receiving interrupts if MSI was
enabled.

Doing a rearm once before getting any interrupts fixes this.

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/pci/base.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/gpu/drm/nouveau/nvkm/subdev/pci/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pci/base.c
@@ -127,6 +127,13 @@ nvkm_pci_init(struct nvkm_subdev *subdev
 		return ret;
 
 	pci->irq = pdev->irq;
+
+	/* Ensure MSI interrupts are armed, for the case where there are
+	 * already interrupts pending (for whatever reason) at load time.
+	 */
+	if (pci->msi)
+		pci->func->msi_rearm(pci);
+
 	return ret;
 }