Re: [PATCH] ahci: separate port number determination from host initialization

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> ahci used to reset controller then fetch cap value to be used for
> configuration.  On some controller this misses some cap bits and ahci
> got modified to maintain cap and ports_impl values over reset, so
> there is no reason to reset the controller before fetching those
> register values.
> 
> Separate out ahci_determine_nr_ports() from ahci_host_init() and it
> before starting to initialize probe_ent.  This makes ahci's init_one
> more consistent to other drivers and eases conversion to new init
> model.
> 
> Also, the initialization is more robust as it doesn't depend on
> ports_impl being writeable when HONOR_PI is set but the register
> itself is zero.
> 
> Tested on ICH7 (no ports_impl) and 8 AHCI (w/ ports_impl).
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>

I would rather make things explicit by creating an 
ahci_read_bios_config() function, and associated data structures, which 
reads all register values that are not preserved across reset.  This 
would also be the code point at which we would handle a 
no-BIOS/uninitialized configuration.

After such a change, this patch will look smaller and nicer.

	Jeff