From 8b794b141c633083408d0bfb2229b3406d0ebf99 Mon Sep 17 00:00:00 2001
From: Maciej Sosnowski <maciej.sosnowski@intel.com>
Date: Thu, 26 Feb 2009 11:04:54 +0100
Subject: I/OAT: fail initialization on zero channels detection

On some systems with I/OAT ver.2 when DCA is disabled in BIOS
situations have been observed
that zero DMA channels are detected instead of four.
To avoid kernel panic driver should fail gracefully with appropriate message.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
index 879f4a0..9012da7 100644
--- a/drivers/dma/ioat_dma.c
+++ b/drivers/dma/ioat_dma.c
@@ -1659,6 +1659,13 @@ struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
 		" %d channels, device version 0x%02x, driver version %s\n",
 		device->common.chancnt, device->version, IOAT_DMA_VERSION);
 
+	if (!device->common.chancnt) {
+		dev_err(&device->pdev->dev,
+			"Intel(R) I/OAT DMA Engine problem found: "
+			"zero channels detected\n");
+		goto err_setup_interrupts;
+	}
+
 	err = ioat_dma_setup_interrupts(device);
 	if (err)
 		goto err_setup_interrupts;
-- 
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