[PATCH] PCI: keystone: add a pci quirk to limit mrrs

Jason Gunthorpe jgunthorpe at obsidianresearch.com
Wed Aug 6 09:58:37 PDT 2014


On Wed, Aug 06, 2014 at 12:56:04PM -0400, Murali Karicheri wrote:
> On 08/06/2014 12:30 PM, Jason Gunthorpe wrote:
> >On Wed, Aug 06, 2014 at 11:18:20AM -0400, Murali Karicheri wrote:
> >>Keystone PCI controller has a limitation that memory read request
> >>size must not exceed 256 bytes. This is a hardware limitation and
> >>add a quirk to force this limit on all downstream devices by
> >>updating mrrs.
> >
> >Does this still work if the tuning is enabled, or does the tuning run
> >after this?
> 
> Yes it works with tuning enabled. Tuning happens afterwards. The
> 'limiting mrrs to 256' below is from my patch.

That seems backwards to me...

Jason



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