Re: [dpdk-dev] [PATCH 04/18] fm10k: add fm10k device id

[David Marchand <david.marchand@6wind.com>]

On Sat, Jan 31, 2015 at 3:19 PM, Neil Horman <nhorman@tuxdriver.com> wrote:

> On Fri, Jan 30, 2015 at 01:07:20PM +0800, Chen Jing D(Mark) wrote:
> > From: Jeff Shaw <jeffrey.b.shaw@intel.com>
> >
> > Add fm10k device ID list into rte_pci_dev_ids.h.
> >
> > Signed-off-by: Jeff Shaw <jeffrey.b.shaw@intel.com>
> > Signed-off-by: Chen Jing D(Mark) <jing.d.chen@intel.com>
> > ---
> >  lib/librte_eal/common/include/rte_pci_dev_ids.h |   22
> ++++++++++++++++++++++
> >  1 files changed, 22 insertions(+), 0 deletions(-)
> >
> > diff --git a/lib/librte_eal/common/include/rte_pci_dev_ids.h
> b/lib/librte_eal/common/include/rte_pci_dev_ids.h
> > index c922de9..f54800e 100644
> > --- a/lib/librte_eal/common/include/rte_pci_dev_ids.h
> > +++ b/lib/librte_eal/common/include/rte_pci_dev_ids.h
> > @@ -132,6 +132,14 @@
> >  #define RTE_PCI_DEV_ID_DECL_VMXNET3(vend, dev)
> >  #endif
> >
> > +#ifndef RTE_PCI_DEV_ID_DECL_FM10K
> > +#define RTE_PCI_DEV_ID_DECL_FM10K(vend, dev)
> > +#endif
> > +
> > +#ifndef RTE_PCI_DEV_ID_DECL_FM10KVF
> > +#define RTE_PCI_DEV_ID_DECL_FM10KVF(vend, dev)
> > +#endif
> > +
> I know this isn't the job of this patch series, but I don't really
> understand
> why we bother with this pattern for filling out pci id tables.  A PMD
> supports
> specific hardware, we might as well use the generic RTE_PCI_DEVICE macro
> in the
> driver rather than creating a FM10K specific wrapper, only to have to do
> some
> ifdef trickery in the rte_cpi_dev_ids file and some include magic to fill
> it
> out.
>

+1


> I'd suggest that you just use RTE_PCI_DEVICE macro here, and make your own
> table
> (keep the specific device id values in the common file.  Then we can clean
> out
> the macro maggic in a later update.
>

If we are going that way, my only concern is that this makes it hard to
"discover" the pci devices that need to be bound to igb_uio/vfio/whatever
kernel driver, and so we must rely either on a global list (like this
rte_pci_dev_ids.h) or on scripts with hardcoded pci device ids in them ...

In the end, we miss something to have dpdk work automatically like it used
to be, before the pci devices ids were stripped out of igb_uio.

I can see two solutions :
- all pmds export the pci device ids they support (this sounds like
modalias :-)) or they register into the eal that exports this information
for use by application, but to me the application should not bother with
this ...
- the pmd handles this automatically (like binding/unbinding on a kernel
driver), with a _runtime_ option to enable this behavior (default being "no
automatic bind")

Comments ? Ideas ?

-- 
David Marchand