On Wed, Jan 06, 2016 at 06:46:37AM +0000, Wang, Annie wrote:

Acpi_dma_xlate  mainly converts an  acpi_dma  structure into a dma_chan structure.
Without proper request line, wrong acpi_dma structure may be get. 

And as Andy says in http://article.gmane.org/gmane.linux.kernel.iommu/11675 
How about add a hook into acpi_dma_controller_register?

Hmm, you can pass custom data in acpi_dma_controller_register() which
will be assigned to adma->data. If you put your request line
information there, I think your custom acpi_dma_xlate() should be able
to use that information to find proper channel, no?