Re: [dpdk-dev] [PATCH v3 1/2] eal/pci: introduce a PCI driver flag

[Thomas Monjalon <thomas@monjalon.net>]

09/06/2017 12:27, Jerin Jacob:
> Some ethdev devices like nicvf thunderx PMD need special treatment for
> Secondary queue set(SQS) PCIe VF devices, where, it expects to not unmap
> or free the memory without registering the ethdev subsystem.
> 
> Introducing a new RTE_PCI_DRV_KEEP_MAPPED_RES
> PCI driver flag to request PCI subsystem to not unmap the mapped PCI
> resources(PCI BAR address) if unsupported device detected.
> 
> Suggested-by: Ferruh Yigit <ferruh.yigit@intel.com>
> Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
[...]
> --- a/lib/librte_eal/common/eal_common_pci.c
> +++ b/lib/librte_eal/common/eal_common_pci.c
> @@ -221,7 +221,12 @@ rte_pci_probe_one_driver(struct rte_pci_driver *dr,
>  	ret = dr->probe(dr, dev);
>  	if (ret) {
>  		dev->driver = NULL;
> -		if (dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING)
> +		if ((dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING) &&
> +			/* Don't unmap if device is unsupported and
> +			 * driver needs mapped resources.
> +			 */
> +			!(ret > 0 &&
> +				(dr->drv_flags & RTE_PCI_DRV_KEEP_MAPPED_RES)))
>  			rte_pci_unmap_device(dev);
>  	}
>  
> --- a/lib/librte_eal/common/include/rte_pci.h
> +++ b/lib/librte_eal/common/include/rte_pci.h
> +/** Device driver needs to keep mapped resources if unsupported dev detected */
> +#define RTE_PCI_DRV_KEEP_MAPPED_RES 0x0020

If I understand well, you want to map resources but not probe it?
Shouldn't it be less hacky to probe it as a (new) null class?