On Wed, Oct 23, 2019 at 09:16:10AM +0000, Nicholas Johnson wrote: > On Tue, Oct 08, 2019 at 03:09:07PM +0300, mika.westerberg@xxxxxxxxxxxxxxx wrote: > > On Fri, Jul 26, 2019 at 12:54:22PM +0000, Nicholas Johnson wrote: > > > Remove checks for resource size in extend_bridge_window(). This is > > > necessary to allow the pci_bus_distribute_available_resources() to > > > function when the kernel parameter pci=hpmemsize=nn[KMG] is used to > > > allocate resources. Because the kernel parameter sets the size of all > > > hotplug bridges to be the same, there are problems when nested hotplug > > > bridges are encountered. Fitting a downstream hotplug bridge with size X > > > and normal bridges with size Y into parent hotplug bridge with size X is > > > impossible, and hence the downstream hotplug bridge needs to shrink to > > > fit into its parent. > > > > Maybe you could show the topology here which needs shrinking. > > > > > Add check for if bridge is extended or shrunken and adjust pci_dbg to > > > reflect this. > > > > > > Reset the resource if its new size is zero (if we have run out of a > > > bridge window resource). If it is set to zero size and left, it can > > > cause significant problems when it comes to enabling devices. > > > > Same comment here about explaining the "significant problems". > I have in the past, but because the problems are very hard to describe succinctly, it just turns into a > nightmare. I can try to do it again. > > > > > > > Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@xxxxxxxxxxxxxx> > > > --- > > > drivers/pci/setup-bus.c | 16 +++++++++++----- > > > 1 file changed, 11 insertions(+), 5 deletions(-) > > > > > > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c > > > index a072781ab..7e1dc892a 100644 > > > --- a/drivers/pci/setup-bus.c > > > +++ b/drivers/pci/setup-bus.c > > > @@ -1823,13 +1823,19 @@ static void extend_bridge_window(struct pci_dev *bridge, struct resource *res, > > > > Since it is also shrinking now maybe name it adjust_bridge_window() instead? > I am happy to do this. > > If we can drop the pci_dbg() calls, then I might be able to drop this > function entirely. During the development of this patch, that is exactly > what I did. How important are the pci_dbg calls to you? Well they are still useful when debugging resource allocation issues (and they match similar we do when extending number of buses). I would like to keep them if possible.
