Re: [PATCH] dmaengine: idxd: add module parameter to force disable of SVA

Vinod Koul
2021-01-26T21:51:04Z

On 19-01-21, 12:44, Dave Jiang wrote:
>
> On 1/19/2021 9:38 AM, Vinod Koul wrote:
> > On 18-01-21, 10:06, Dave Jiang wrote:
> > > On 1/16/2021 11:51 PM, Vinod Koul wrote:
> > > > On 15-01-21, 15:01, Dave Jiang wrote:
> > > > > Add a module parameter that overrides the SVA feature enabling. This keeps
> > > > > the driver in legacy mode even when intel_iommu=sm_on is set. In this mode,
> > > > > the descriptor fields must be programmed with dma_addr_t from the Linux DMA
> > > > > API for source, destination, and completion descriptors.
> > > > >
> > > > > Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> > > > > ---
> > > > > drivers/dma/idxd/init.c | 8 +++++++-
> > > > > 1 file changed, 7 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> > > > > index 25cc947c6179..9687a24ff982 100644
> > > > > --- a/drivers/dma/idxd/init.c
> > > > > +++ b/drivers/dma/idxd/init.c
> > > > > @@ -26,6 +26,10 @@ MODULE_VERSION(IDXD_DRIVER_VERSION);
> > > > > MODULE_LICENSE("GPL v2");
> > > > > MODULE_AUTHOR("Intel Corporation");
> > > > > +static bool sva = true;
> > > > > +module_param(sva, bool, 0644);
> > > > > +MODULE_PARM_DESC(sva, "Toggle SVA support on/off");
> > > > Documentation for this please..
> > > Just comments or is there somewhere specific for driver module parameter
> > > documentations?
> > All the parameters are supposed to be documented in Documentation/admin-guide/kernel-parameters.txt
>
> It seems to be for core kernel components and subsystems, and not specific
> device drivers. I'm not seeing any of the dmaengine driver module params
> being in this doc after grepping in drivers/dma.

Yeah we should fix that as well :)

--
~Vinod