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| author | Luca Tettamanti <kronos.it@gmail.com> | 2007-11-24 13:15:18 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-12-14 10:31:54 -0800 |
| commit | 25487152280c34be57e548a4e82b67906ef2c1c1 (patch) | |
| tree | 4e702bf1ae4d010d11aa4a5ec71bb733e9cc6279 /drivers | |
| parent | 3f7153e947a301a5567cb50866479006575757e5 (diff) | |
| download | lwn-25487152280c34be57e548a4e82b67906ef2c1c1.tar.gz lwn-25487152280c34be57e548a4e82b67906ef2c1c1.zip | |
atl1: disable broken 64-bit DMA
atl1: disable broken 64-bit DMA
[ Upstream commit: 5f08e46b621a769e52a9545a23ab1d5fb2aec1d4 ]
The L1 network chip can DMA to 64-bit addresses, but multiple descriptor
rings share a single register for the high 32 bits of their address, so
only a single, aligned, 4 GB physical address range can be used at a time.
As a result, we need to confine the driver to a 32-bit DMA mask, otherwise
we see occasional data corruption errors in systems containing 4 or more
gigabytes of RAM.
Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Jay Cliburn <jacliburn@bellsouth.net>
Acked-by: Chris Snook <csnook@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/atl1/atl1_main.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/drivers/net/atl1/atl1_main.c b/drivers/net/atl1/atl1_main.c index 6862c11ff864..1b7a5a894ab8 100644 --- a/drivers/net/atl1/atl1_main.c +++ b/drivers/net/atl1/atl1_main.c @@ -2097,21 +2097,26 @@ static int __devinit atl1_probe(struct pci_dev *pdev, struct net_device *netdev; struct atl1_adapter *adapter; static int cards_found = 0; - bool pci_using_64 = true; int err; err = pci_enable_device(pdev); if (err) return err; - err = pci_set_dma_mask(pdev, DMA_64BIT_MASK); + /* + * The atl1 chip can DMA to 64-bit addresses, but it uses a single + * shared register for the high 32 bits, so only a single, aligned, + * 4 GB physical address range can be used at a time. + * + * Supporting 64-bit DMA on this hardware is more trouble than it's + * worth. It is far easier to limit to 32-bit DMA than update + * various kernel subsystems to support the mechanics required by a + * fixed-high-32-bit system. + */ + err = pci_set_dma_mask(pdev, DMA_32BIT_MASK); if (err) { - err = pci_set_dma_mask(pdev, DMA_32BIT_MASK); - if (err) { - dev_err(&pdev->dev, "no usable DMA configuration\n"); - goto err_dma; - } - pci_using_64 = false; + dev_err(&pdev->dev, "no usable DMA configuration\n"); + goto err_dma; } /* Mark all PCI regions associated with PCI device * pdev as being reserved by owner atl1_driver_name @@ -2176,7 +2181,6 @@ static int __devinit atl1_probe(struct pci_dev *pdev, netdev->ethtool_ops = &atl1_ethtool_ops; adapter->bd_number = cards_found; - adapter->pci_using_64 = pci_using_64; /* setup the private structure */ err = atl1_sw_init(adapter); @@ -2193,9 +2197,6 @@ static int __devinit atl1_probe(struct pci_dev *pdev, */ /* netdev->features |= NETIF_F_TSO; */ - if (pci_using_64) - netdev->features |= NETIF_F_HIGHDMA; - netdev->features |= NETIF_F_LLTX; /* |