Re: [PATCH v3 4/9] PCI/VGA: Improve the default VGA device selection

[suijingfeng <suijingfeng@xxxxxxxxxxx>]

Hi,


Thanks for you noticed my change.


On 2023/7/20 03:32, Bjorn Helgaas wrote:
> > @@ -1509,13 +1543,24 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
> >   	 * cases of hotplugable vga cards.
> >   	 */
> >   
> > -	if (action == BUS_NOTIFY_ADD_DEVICE)
> > +	switch (action) {
> > +	case BUS_NOTIFY_ADD_DEVICE:
> >   		notify = vga_arbiter_add_pci_device(pdev);
> > -	else if (action == BUS_NOTIFY_DEL_DEVICE)
> > +		if (notify)
> > +			vga_arbiter_notify_clients();
> > +		break;
> > +	case BUS_NOTIFY_DEL_DEVICE:
> >   		notify = vga_arbiter_del_pci_device(pdev);
> > +		if (notify)
> > +			vga_arbiter_notify_clients();
> > +		break;
> > +	case BUS_NOTIFY_BOUND_DRIVER:
> > +		vga_arbiter_do_arbitration(pdev);
> > +		break;
> > +	default:
> > +		break;
> > +	}
> Changing from if/else to switch makes the patch bigger than necessary
> for no real benefit and obscures what is really changing.

Actually, the logic become more clear after this patch applied.

```

    switch (action) {
    case BUS_NOTIFY_ADD_DEVICE:
        notify = vga_arbiter_add_pci_device(pdev);
        if (notify)
            vga_arbiter_notify_clients();
        break;
    case BUS_NOTIFY_DEL_DEVICE:
        notify = vga_arbiter_del_pci_device(pdev);
        if (notify)
            vga_arbiter_notify_clients();
        break;
    case BUS_NOTIFY_BOUND_DRIVER:
        vga_arbiter_do_arbitration(pdev);
        break;
    default:
        break;
    }

```


Because we only need call vga_arbiter_notify_clients() when action == 
BUS_NOTIFY_ADD_DEVICE or action == BUS_NOTIFY_DEL_DEVICE,

But *NOT* when the action equals to  BUS_NOTIFY_BOUND_DRIVER.