Re: [dpdk-dev] [PATCH] pci: Don't call probe callback if driver already loaded.

[Shreyansh Jain <shreyansh.jain@nxp.com>]

On 10/26/2016 3:20 AM, Ben Walker wrote:
> If the user asks to probe multiple times, the probe
> callback should only be called on devices that don't have
> a driver already loaded.
>
> This is useful if a driver is registered after the
> execution of a program has started and the list of devices
> needs to be re-scanned.
>
> Signed-off-by: Ben Walker <benjamin.walker@intel.com>
> ---
>  lib/librte_eal/common/eal_common_pci.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/lib/librte_eal/common/eal_common_pci.c b/lib/librte_eal/common/eal_common_pci.c
> index 638cd86..971ad20 100644
> --- a/lib/librte_eal/common/eal_common_pci.c
> +++ b/lib/librte_eal/common/eal_common_pci.c
> @@ -289,6 +289,10 @@ pci_probe_all_drivers(struct rte_pci_device *dev)
>  	if (dev == NULL)
>  		return -1;
>
> +	/* Check if a driver is already loaded */
> +	if (dev->driver != NULL)
> +		return 0;
> +

In case if it is required to change the driver assigned to a device, would it mean application relies on detach(dev)->new-driver-plugged-in->attach(dev) sequence?
To me, the above change sounds fine. Though, I am not aware if there is even a use case for changing driver assigned to a device. detach()->attach() should be able to work in those cases, I think.

>  	TAILQ_FOREACH(dr, &pci_driver_list, next) {
>  		rc = rte_eal_pci_probe_one_driver(dr, dev);
>  		if (rc < 0)
>

-
Shreyansh