Re: [PATCH #upstream, v2] ahci: Implement SATA AHCI FIS-based switching support

[Tejun Heo <tj@kernel.org>]

Hello, Shane.

Huang, Shane wrote:
> static void ahci_enable_fbs(struct ata_port *ap)
> {
> 	struct ahci_port_priv *pp = ap->private_data;
> 	void __iomem *port_mmio = ahci_port_base(ap);
> 	u32 fbs;
> 	int rc;
> 
> 	if (!pp->fbs_supported)
> 		return;
> 
> 	fbs = readl(port_mmio + PORT_FBS);
> 	if (fbs & PORT_FBS_EN)
> 		return;

This can leave pp->fbs_enabled out of sync, right?  Just don't check
and set the bit anyway.

> 	rc = ahci_stop_engine(ap);
> 	if (rc)
> 		return;
> 
> 	writel(fbs | PORT_FBS_EN, port_mmio + PORT_FBS);
> 	fbs = readl(port_mmio + PORT_FBS);
> 	if (fbs & PORT_FBS_EN) {
> 		dev_printk(KERN_INFO, ap->host->dev, "FBS is
> enabled.\n");
> 		pp->fbs_enabled = true;
> 		pp->fbs_last_dev = -1; /* initialization */
> 	} else
> 		dev_printk(KERN_ERR, ap->host->dev, "Failed to enable
> FBS\n");
> 
> 	ahci_start_engine(ap);
> }
> 
> 
> static void ahci_disable_fbs(struct ata_port *ap)
> {
> 	struct ahci_port_priv *pp = ap->private_data;
> 	void __iomem *port_mmio = ahci_port_base(ap);
> 	u32 fbs;
> 	int rc;
> 
> 	if (!pp->fbs_supported)
> 		return;
> 
> 	fbs = readl(port_mmio + PORT_FBS);
> 	if ((fbs & PORT_FBS_EN) == 0)
> 		return;

Ditto.

Thanks.

-- 
tejun