Re: [PATCH] Introducing kernel option to force all PCI memory resources to be page aligned. Fixes issues with uio based drivers.

["gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>]

On Mon, Jun 06, 2016 at 06:53:28AM +0000, Koehrer Mathias (ETAS/ESW5) wrote:
> Some uio based PCI drivers (e.g. uio_cif) do not work if the assigned 
> PCI memory resources are not page aligned.
> By using the kernel option "pci=resource_alignment" it is possible to force
> single PCI boards to use page alignment for their memory resources.
> However, this is fairly cumbersome if multiple of these cards are in use.
> This patch adds another kernel option "pci=resources_page_aligned"
> that allows to set the default alignment of PCI memory resources to
> be page aligned.
> Overwriting of this default alignment via "pci=resource_alignment" is
> still possible.

This seems like a very large hammer for a very specific problem with a
card that seems to be not-in-spec (I can't find anywhere that requires
resources to be "page" aligned in the PCI spec).  Why not fix the
firmware in these cards?

thanks,

greg k-h