From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <shemminger@vyatta.com>
Subject: [RFT] sky2: 32 bit DMA quirk
Date: Wed, 7 Dec 2011 15:02:05 -0800
Message-ID: <20111207150205.3fad9290@nehalam.linuxnetplumber.net>
References: <20111120232118.GA29748@ntm.wq.cz>
	<20111121160543.2ae9c04c@nehalam.linuxnetplumber.net>
	<20111122094234.GA28500@ntm.wq.cz>
	<20111126161513.GA5299@ntm.wq.cz>
	<20111126170331.744025f1@s6510.linuxnetplumber.net>
	<20111205124725.GA19385@ntm.wq.cz>
	<20111205081611.52ec0664@nehalam.linuxnetplumber.net>
	<20111206095919.GA6726@ntm.wq.cz>
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This a patch to force 32 bit DMA. Not sure if the DMI values
are right for the Gigabyte motherboard with the problem.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

--- a/drivers/net/ethernet/marvell/sky2.c	2011-12-07 10:54:18.816279159 -0800
+++ b/drivers/net/ethernet/marvell/sky2.c	2011-12-07 14:59:47.737381388 -0800
@@ -41,6 +41,7 @@
 #include <linux/delay.h>
 #include <linux/workqueue.h>
 #include <linux/if_vlan.h>
+#include <linux/dmi.h>
 #include <linux/prefetch.h>
 #include <linux/debugfs.h>
 #include <linux/mii.h>
@@ -95,6 +96,10 @@ static int disable_msi = 0;
 module_param(disable_msi, int, 0);
 MODULE_PARM_DESC(disable_msi, "Disable Message Signaled Interrupt (MSI)");
 
+static int only_32bit_dma;
+module_param(only_32bit_dma, int, 0);
+MODULE_PARM_DESC(only_32bit_dma, "Limit device to 32 bit DMA access");
+
 static DEFINE_PCI_DEVICE_TABLE(sky2_id_table) = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_SYSKONNECT, 0x9000) }, /* SK-9Sxx */
 	{ PCI_DEVICE(PCI_VENDOR_ID_SYSKONNECT, 0x9E00) }, /* SK-9Exx */
@@ -4889,7 +4894,7 @@ static int __devinit sky2_probe(struct p
 
 	pci_set_master(pdev);
 
-	if (sizeof(dma_addr_t) > sizeof(u32) &&
+	if (sizeof(dma_addr_t) > sizeof(u32) && !only_32bit_dma &&
 	    !(err = pci_set_dma_mask(pdev, DMA_BIT_MASK(64)))) {
 		using_dac = 1;
 		err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
@@ -5163,10 +5168,24 @@ static struct pci_driver sky2_driver = {
 	.driver.pm = SKY2_PM_OPS,
 };
 
+static struct dmi_system_id sky2_32bit_dma_boards[] = {
+	{
+		.ident = "Gigabyte GA-965GM-S2 boards",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Gigabyte Technology Co"),
+			DMI_MATCH(DMI_BOARD_NAME, "GA-965GM-S2"),
+		},
+	},
+	{}
+};
+
 static int __init sky2_init_module(void)
 {
 	pr_info("driver version " DRV_VERSION "\n");
 
+	if (dmi_check_system(sky2_32bit_dma_boards))
+		only_32bit_dma = 1;
+
 	sky2_debug_init();
 	return pci_register_driver(&sky2_driver);
 }