From: Maciej Sosnowski <maciej.sosnowski@intel.com>
Date: Thu, 26 Feb 2009 10:04:54 +0000 (+0100)
Subject: I/OAT: fail initialization on zero channels detection
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=8b794b141c633083408d0bfb2229b3406d0ebf99;p=linux-2.6-omap-h63xx.git

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 879f4a06e3c..9012da7908f 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;