Re: [PATCH 4/6] PCI: acpiphp: check for new devices on enabled host

From: Kirill A. Shutemov
Date: Wed Jun 26 2013 - 05:37:21 EST


Andy Shevchenko wrote:
> On Tue, Jun 25, 2013 at 7:22 PM, Mika Westerberg
> <mika.westerberg@xxxxxxxxxxxxxxx> wrote:
>
> > Current acpiphp_check_bridge() implementation is pretty dumb:
> > - it enables the slot if it's not enabled and the slot status is
> > ACPI_STA_ALL;
> > - it disables the slot if it's enabled and slot is not in ACPI_STA_ALL
> > state.
> >
> > This behavior is not enough to handle Thunderbolt chaining case
> > properly. We need to actually rescan for new devices even if a device
> > has already in the slot.
> >
> > The new implementation disables and stops the slot if it's not in
> > ACPI_STA_ALL state.
> >
> > For ACPI_STA_ALL state we first trim devices which don't respond and
> > look for the ones after that. We do that even if slot already enabled
> > (SLOT_ENABLED).
>
> Just a couple of nitpicks below.
>
> > list_for_each_entry(slot, &bridge->slots, node) {
> > + struct pci_bus *bus = slot->bridge->pci_bus;
> > + struct pci_dev *dev, *tmp;
> > + int retval;
> > +
> > + mutex_lock(&slot->crit_sect);
>
> Does it make sense to introduce a helper let's say
> __acpiphp_check_slot() and put there all lines inside this mutex?

No. Why?

> > + if (get_slot_status(slot) == ACPI_STA_ALL) {
> > + /* remove stale devices if any */
> > + list_for_each_entry_safe(dev, tmp,
> > + &bus->devices, bus_list) {
> > + if (PCI_SLOT(dev->devfn) != slot->device)
> > + continue;
> > + pci_trim_stale_devices(dev);
>
> Perhaps
>
> list_for_each_entry_safe(dev, tmp, &bus->devices, bus_list) {
> if (PCI_SLOT(dev->devfn) == slot->device)
> pci_trim_stale_devices(dev);
> }

Makes sense, thanks.

--
Kirill A. Shutemov
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