On Tue, Feb 23, 2021 at 11:00:54AM -0500, Alan Stern wrote: > The impression I get is that Greg would like the USB core to export a > function which takes struct usb_interface * as argument and returns the > appropriate DMA mask value. Then instead of messing around with USB > internals, drm_gem_prime_import_usb could just call this new function. > > Adding such a utility function would be a sufficiently small change that > it could go into the -stable kernels with no trouble. The DMA mask value on its own is not useful. It needs to be paired with a device that the dma API functions can be called on.
