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authorNate Dailey <nate.dailey@stratus.com>2007-02-15 18:13:46 -0500
committerJeff Garzik <jeff@garzik.org>2007-02-15 18:13:46 -0500
commit7de970e11fb832a56c897276967fb0e49f59b313 (patch)
tree6e49d7e80c9b3f847a3d6bd84ccbf70614a2ef1d
parent5278b50cea851d8264b7b28212a483328650476f (diff)
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: Nate Dailey <nate.dailey@stratus.com> Signed-off-by: Jeremy Higdon <jeremy@sgi.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
-rw-r--r--drivers/ata/sata_vsc.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/ata/sata_vsc.c b/drivers/ata/sata_vsc.c
index 3d9daf231115..2fd037bde090 100644
--- a/drivers/ata/sata_vsc.c
+++ b/drivers/ata/sata_vsc.c
@@ -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);