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

[Tejun Heo <tj@kernel.org>]

Hello, Shane.

Huang, Shane wrote:
> Quoting myself:
>> 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;
>>
>> 	WARN_ON(!pp->fbs_enabled);
>>
>> 	rc = ahci_stop_engine(ap);
> 
> I find that ahci_pmp_detach() will be called for each SATA port
> during the initialization, right after print:
>> ahci 0000:00:11.0: flags: 64bit ncq sntf ilck pm led clo pmp fbs...
> 
> so will ahci_disable_fbs() be called, which leads to the trigger
> of WARN_ON().

Ah.. right.  ahci_port_resume() does that to make sure that all PMP
bits are cleared on init.  Hmmm... probably it would be better to make
ahci_disable_fbs() to just do it regardless of libata thinks whether
PMP is attached or not.  After resume from STR, we shouldn't be
assuming anything about the controller state.

Thanks.

-- 
tejun