[PATCH 2.6.9-rc2 1/1] r8169: default on disabling PCIDAC

[Francois Romieu <romieu@xxxxxxxxxxxxx>]

Default to disabling PCI DAC as this option appears unsafe on amd64
(original suggestion by Hans-Frieder Vogt <hfvogt@xxxxxxxx>).

The driver will typically report PCI System error when something goes
wrong. The relevant interrupt is not masked any more and the driver
can thus be disabled.

Signed-off-by: Francois Romieu <romieu@xxxxxxxxxxxxx>

diff -puN linux-2.6.9-rc2.orig/drivers/net/r8169.c 
linux-2.6.9-rc2/drivers/net/r8169.c
--- linux-2.6.9-rc2.orig/drivers/net/r8169.c    2004-09-19 00:17:04.000000000 
+0200
+++ linux-2.6.9-rc2/drivers/net/r8169.c 2004-09-20 00:16:02.000000000 +0200
@@ -156,6 +156,7 @@ static struct pci_device_id rtl8169_pci_
 MODULE_DEVICE_TABLE(pci, rtl8169_pci_tbl);
 
 static int rx_copybreak = 200;
+static int use_dac;
 
 enum RTL8169_registers {
        MAC0 = 0,               /* Ethernet hardware address. */
@@ -358,6 +359,8 @@ MODULE_AUTHOR("Realtek");
 MODULE_DESCRIPTION("RealTek RTL-8169 Gigabit Ethernet driver");
 MODULE_PARM(media, "1-" __MODULE_STRING(MAX_UNITS) "i");
 MODULE_PARM(rx_copybreak, "i");
+MODULE_PARM(use_dac, "i");
+MODULE_PARM_DESC(use_dac, "Enable PCI DAC. Unsafe on 32 bit PCI slot.");
 MODULE_LICENSE("GPL");
 
 static int rtl8169_open(struct net_device *dev);
@@ -375,7 +378,7 @@ static int rtl8169_poll(struct net_devic
 #endif
 
 static const u16 rtl8169_intr_mask =
-       LinkChg | RxOverflow | RxFIFOOver | TxErr | TxOK | RxErr | RxOK;
+       SYSErr | LinkChg | RxOverflow | RxFIFOOver | TxErr | TxOK | RxErr | 
RxOK;
 static const u16 rtl8169_napi_event =
        RxOK | RxOverflow | RxFIFOOver | TxOK | TxErr;
 static const unsigned int rtl8169_rx_config =
@@ -984,7 +987,7 @@ rtl8169_init_board(struct pci_dev *pdev,
        tp->cp_cmd = PCIMulRW | RxChkSum;
 
        if ((sizeof(dma_addr_t) > 4) &&
-           !pci_set_dma_mask(pdev, DMA_64BIT_MASK))
+           !pci_set_dma_mask(pdev, DMA_64BIT_MASK) && use_dac)
                tp->cp_cmd |= PCIDAC;
        else {
                rc = pci_set_dma_mask(pdev, DMA_32BIT_MASK);
@@ -1761,6 +1764,15 @@ rtl8169_interrupt(int irq, void *dev_ins
                if (!(status & rtl8169_intr_mask))
                        break;
 
+               if (unlikely(status & SYSErr)) {
+                       printk(KERN_ERR PFX "%s: PCI error (status: 0x%04x)."
+                              " Device disabled.\n", dev->name, status);
+                       RTL_W8(ChipCmd, 0x00);
+                       RTL_W16(IntrMask, 0x0000);
+                       RTL_R16(IntrMask);
+                       break;
+               }
+
                if (status & LinkChg)
                        rtl8169_check_link_status(dev, tp, ioaddr);