Re: Who's responsible for configuring CLS on a cardbus device?

[Alan Cox]

On Tue, 26 May 2009 22:05:08 +0900
Tejun Heo <tj@xxxxxxxxxx> wrote:

> Hello,
> 
> This is regarding bko#13257.
> 
>  http://bugzilla.kernel.org/show_bug.cgi?id=13257
> 
> towerlexa@xxxxxx was experiencing very slow transfer rate when using a
> cardbus sata_sil SATA controller which is known to be sensitive to
> cache line size setting.  The reset default is zero and no one
> configured it causing poor performance.
> 
> This is solvable by simply setting CLS to the correct value but who's
> job is it?  For non-hotplug devices, this is configured by the BIOS
> (at least on PC), so for hotplug devices I think falls on the lap of
> the PCI code but I'm not sure.  If this is something which the
> sata_sil driver should be responsible for, is there an established way
> to determine the proper CLS value?

Currently its handled by pci_set_mwi() but there isn't actually a more
direct way to do this.

Alan
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