Messages in this thread | | | From | H Hartley Sweeten <> | Date | Mon, 12 Nov 2012 17:13:52 -0600 | Subject | RE: Q: Kconfig option VIRT_TO_BUS |
| |
On Monday, November 12, 2012 11:41 AM, Bjorn Helgaas wrote: > On Mon, Nov 12, 2012 at 9:18 AM, H Hartley Sweeten wrote: >> Does anyone know what the Kconfig option VIRT_TO_BUS does? >> There are a number of "depends on" that option but it does not >> seem to directly enable any code in the kernel. > > virt_to_bus() is a deprecated interface for converting a kernel > virtual address to a bus address. It's deprecated because it's > impossible to implement correctly when there are multiple bus address > spaces, because you don't know which bus address space the caller has > in mind.
Thanks for the info.
So if a driver does not use virt_to_bus() then the "depends on VIRT_TO_BUS" is not necessary. Correct?
Thanks, Hartley
| |