提交 7de970e1 编写于 作者: N Nate Dailey 提交者: Jeff Garzik

sata_vsc: use default cache line size if non-zero

This modifies drivers/ata/sata_vsc.c to only set the cache line size
to 0x80 if the default value is zero. Apparently zero isn't allowed
due to a bug in the chip, but I've found performance is much better
with the (non-zero) default instead of 0x80.

[note1: "default" means BIOS-programmed value, in this context -jgarzik]

[note2: superfluous braces were removed from the patch -jg]
Signed-off-by: NNate Dailey <nate.dailey@stratus.com>
Signed-off-by: NJeremy Higdon <jeremy@sgi.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>
上级 5278b50c
......@@ -346,6 +346,7 @@ static int __devinit vsc_sata_init_one (struct pci_dev *pdev, const struct pci_d
struct ata_probe_ent *probe_ent;
void __iomem *mmio_base;
int rc;
u8 cls;
if (!printed_version++)
dev_printk(KERN_DEBUG, &pdev->dev, "version " DRV_VERSION "\n");
......@@ -383,9 +384,12 @@ static int __devinit vsc_sata_init_one (struct pci_dev *pdev, const struct pci_d
INIT_LIST_HEAD(&probe_ent->node);
/*
* Due to a bug in the chip, the default cache line size can't be used
* Due to a bug in the chip, the default cache line size can't be
* used (unless the default is non-zero).
*/
pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE, 0x80);
pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &cls);
if (cls == 0x00)
pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE, 0x80);
if (pci_enable_msi(pdev) == 0)
pci_intx(pdev, 0);
......
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