[PATCH 2.6.9-rc3-mm2 3/5] r8169: automatic pci dac step down

[Francois Romieu <romieu@xxxxxxxxxxxxx>]

Automatic adjustement of highmem dma feature.

The first interruption encountered on systems where the 8169 does not
perform PCI DAC correctly seems to always be a PCI error one.
When DAC is enabled, the driver tries to issue a complete down/up
sequence as an addition to the usual halt of the device.

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

diff -puN drivers/net/r8169.c~r8169-210 drivers/net/r8169.c
--- linux-2.6.9-rc3/drivers/net/r8169.c~r8169-210       2004-10-04 
21:18:14.000000000 +0200
+++ linux-2.6.9-rc3-fr/drivers/net/r8169.c      2004-10-04 21:25:07.000000000 
+0200
@@ -1716,6 +1716,34 @@ static void rtl8169_schedule_work(struct
        schedule_delayed_work(&tp->task, 4);
 }
 
+static void rtl8169_wait_for_quiescence(struct net_device *dev)
+{
+       synchronize_irq(dev->irq);
+
+       /* Wait for any pending NAPI task to complete */
+       netif_poll_disable(dev);
+}
+
+static void rtl8169_reinit_task(void *_data)
+{
+       struct net_device *dev = _data;
+       int ret;
+
+       if (netif_running(dev)) {
+               rtl8169_wait_for_quiescence(dev);
+               rtl8169_close(dev);
+       }
+
+       ret = rtl8169_open(dev);
+       if (unlikely(ret < 0)) {
+               if (net_ratelimit()) {
+                       printk(PFX KERN_ERR "%s: reinit failure (status = %d)."
+                              " Rescheduling.\n", dev->name, ret);
+               }
+               rtl8169_schedule_work(dev, rtl8169_reinit_task);
+       }
+}
+
 static void rtl8169_reset_task(void *_data)
 {
        struct net_device *dev = _data;
@@ -1724,10 +1752,7 @@ static void rtl8169_reset_task(void *_da
        if (!netif_running(dev))
                return;
 
-       synchronize_irq(dev->irq);
-
-       /* Wait for any pending NAPI task to complete */
-       netif_poll_disable(dev);
+       rtl8169_wait_for_quiescence(dev);
 
        rtl8169_rx_interrupt(dev, tp, tp->mmio_addr);
        rtl8169_tx_clear(tp);
@@ -1893,6 +1918,46 @@ err_update_stats:
        goto out;
 }
 
+static void rtl8169_pcierr_interrupt(struct net_device *dev)
+{
+       struct rtl8169_private *tp = netdev_priv(dev);
+       struct pci_dev *pdev = tp->pci_dev;
+       void *ioaddr = tp->mmio_addr;
+       u16 pci_status, pci_cmd;
+
+       pci_read_config_word(pdev, PCI_COMMAND, &pci_cmd);
+       pci_read_config_word(pdev, PCI_STATUS, &pci_status);
+
+       printk(KERN_ERR PFX "%s: PCI error (cmd = 0x%04x, status = 0x%04x).\n",
+              dev->name, pci_cmd, pci_status);
+
+       /*
+        * The recovery sequence below admits a very elaborated explanation:
+        * - it seems to work;
+        * - I did not see what else could be done.
+        *
+        * Feel free to adjust to your needs.
+        */
+       pci_write_config_word(pdev, PCI_COMMAND,
+                             pci_cmd | PCI_COMMAND_SERR | PCI_COMMAND_PARITY);
+
+       pci_write_config_word(pdev, PCI_STATUS,
+               pci_status & (PCI_STATUS_DETECTED_PARITY |
+               PCI_STATUS_SIG_SYSTEM_ERROR | PCI_STATUS_REC_MASTER_ABORT |
+               PCI_STATUS_REC_TARGET_ABORT | PCI_STATUS_SIG_TARGET_ABORT));
+
+       /* The infamous DAC f*ckup only happens at boot time */
+       if ((tp->cp_cmd & PCIDAC) && (tp->dirty_rx == tp->cur_rx == 0)) {
+               printk(KERN_INFO PFX "%s: disabling PCI DAC.\n", dev->name);
+               tp->cp_cmd &= ~PCIDAC;
+               RTL_W16(CPlusCmd, tp->cp_cmd);
+               dev->features &= ~NETIF_F_HIGHDMA;
+               rtl8169_schedule_work(dev, rtl8169_reinit_task);
+       }
+
+       rtl8169_hw_reset(ioaddr);
+}
+
 static void
 rtl8169_tx_interrupt(struct net_device *dev, struct rtl8169_private *tp,
                     void *ioaddr)
@@ -2094,9 +2159,7 @@ rtl8169_interrupt(int irq, void *dev_ins
                        break;
 
                if (unlikely(status & SYSErr)) {
-                       printk(KERN_ERR PFX "%s: PCI error (status: 0x%04x)."
-                              " Device disabled.\n", dev->name, status);
-                       rtl8169_hw_reset(ioaddr);
+                       rtl8169_pcierr_interrupt(dev);
                        break;
                }
 

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