[PATCH 4.12 37/43] ahci: dont use MSI for devices with the silly Intel NVMe remapping scheme - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, John Loy <john.robert.loy@gmail.com>,
	Christoph Hellwig <hch@lst.de>, Tejun Heo <tj@kernel.org>
Subject: [PATCH 4.12 37/43] ahci: dont use MSI for devices with the silly Intel NVMe remapping scheme
Date: Fri,  8 Sep 2017 15:19:25 +0200	[thread overview]
Message-ID: <20170908131827.908720463@linuxfoundation.org> (raw)
In-Reply-To: <20170908131826.555428826@linuxfoundation.org>

4.12-stable review patch.  If anyone has any objections, please let me know.

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

From: Christoph Hellwig <hch@lst.de>

commit f723fa4e69920f6a5dd5fa0d10ce90e2f14d189c upstream.

Intel AHCI controllers that also hide NVMe devices in their bar
can't use MSI interrupts, so disable them.

Reported-by: John Loy <john.robert.loy@gmail.com>
Tested-by: John Loy <john.robert.loy@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Fixes: d684a90d38e2 ("ahci: per-port msix support")
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/ata/ahci.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1467,7 +1467,14 @@ static void ahci_remap_check(struct pci_
 		return;
 
 	dev_warn(&pdev->dev, "Found %d remapped NVMe devices.\n", count);
-	dev_warn(&pdev->dev, "Switch your BIOS from RAID to AHCI mode to use them.\n");
+	dev_warn(&pdev->dev,
+		 "Switch your BIOS from RAID to AHCI mode to use them.\n");
+
+	/*
+	 * Don't rely on the msi-x capability in the remap case,
+	 * share the legacy interrupt across ahci and remapped devices.
+	 */
+	hpriv->flags |= AHCI_HFLAG_NO_MSI;
 }
 
 static int ahci_get_irq_vector(struct ata_host *host, int port)
