sata_vsc: use default cache line size if non-zero (7de970e1) · Commits · 戴 / test

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>

drivers/ata/sata_vsc.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -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");
		@@ -383,8 +384,11 @@ 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_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)

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