From 7de970e11fb832a56c897276967fb0e49f59b313 Mon Sep 17 00:00:00 2001 From: Nate Dailey Date: Thu, 15 Feb 2007 18:13:46 -0500 Subject: [PATCH] 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 Signed-off-by: Jeremy Higdon Signed-off-by: Jeff Garzik --- drivers/ata/sata_vsc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/ata/sata_vsc.c b/drivers/ata/sata_vsc.c index 3d9daf23111..2fd037bde09 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); -- 2.41.1