On Thu, Apr 14, 2022 at 3:59 PM Andrew Scull <asc...@google.com> wrote: > > On Thu, 14 Apr 2022 at 01:42, Bin Meng <bmeng...@gmail.com> wrote: > > > > On Thu, Apr 14, 2022 at 12:30 AM Andrew Scull <asc...@google.com> wrote: > > > > > > > > diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig > > > > > index 47cd074aa1..fd2203420c 100644 > > > > > --- a/drivers/pci/Kconfig > > > > > +++ b/drivers/pci/Kconfig > > > > > @@ -67,6 +67,13 @@ config PCI_SRIOV > > > > > if available on a PCI Physical Function device and probe for > > > > > applicable drivers. > > > > > > > > > > +config PCI_ENHANCED_ALLOCATION > > > > > + bool "Enable support for Enhanced Allocation of resources" > > > > > + default y > > > > > + help > > > > > + Enable support for Enhanced Allocation which can be used by > > > > > supported > > > > > + devices in place of traditional BARS for allocation of > > > > > resources. > > > > > + > > > > > > > > Why do we need a config option for EA as it can be figured out in the > > > > run time? > > > > > > I wanted to have the option to disable the logic for handling EA at > > > runtime. A glance at the code suggested there's a whole other rabbit > > > hole of missing safety checks that I've opted to leave for another > > > day. > > > > We cannot have a single global option to work for one device using EA > > but another device using BAR. > > Sorry, I don't understand what you mean. This config will just mean > the u-boot doesn't look for, or handle, the EA capability; it disables > u-boot's support for this feature. If a system relies on EA, they'll > need to have it enabled which is the default state. If a system > doesn't then it can be turned off and the suspect logic disabled. > > Could you help me understand your concern?
I was thinking of 2 PCI devices, one uses the normal BAR mechanism while the other one uses the EA. In such a case, this config option is mandated to be turned on. I just see no value in providing a config option while it can be determined at runtime. Is that for footprint or some other concern why you wanted to introduce it? Regards, Bin