On 01/17/2010 09:34 AM, Jesse Barnes wrote: > On Sat, 16 Jan 2010 16:14:31 -0700 > Bjorn Helgaas <bjorn.helgaas@xxxxxx> wrote: > >> On Sat, 2010-01-16 at 01:34 -0800, Yinghai Lu wrote: >>> On 01/15/2010 08:59 PM, Alex Chiang wrote: >>>> * Yinghai Lu <yinghai@xxxxxxxxxx>: >>>>> From: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx> >>>>> >>>>> With this patch, pciehp driver try to clear PCI bridge resources >>>>> to parent bridge (root port or switch downstream port) of the >>>>> slot >>>>> >>>>> so we can shrink pci bridge resource for those port >>>>> >>>>> This feature is enabled when 'pciehp_realloc' option is >>>>> specified. >>>>> >>>>> -v2: make it could be appiled after Yinghai patchset that touch >>>>> pci bridge resource also remove poweron check, because >>>>> pci_bridge_release_res will check child at first >>>> >>>> Same comment as my earlier patch. Why not just make this the >>>> default behavior, instead of introducing yet another command line >>>> parameter for users to guess at? >>> >>> it will break Eric's setup/ >> >> I think this is a clue that we don't understand the problem well >> enough yet. >> >> I'm opposed to adding kernel parameters for this sort of thing. It is >> unreasonable to expect users to figure out whether they need to use >> this parameter or not. >> >> Special-case switches like this make it much harder to maintain the >> code in the future. > > Agreed. Yinghai, what's wrong in the new reassignment code that > causes Eric's setup to break? Can we just fix that instead and enable > reallocation by default? no. Eric's setup is: hot plug one addon card into one hotplug slots and new addon cards have more hot plug slots. SLOTA will have SLOT B, SLOT C, and SLOT D as children. and not devices in SLOTB/C/D at first. with the pciehp_realloc is specified, the SLOTA will not get any device assigned, and later if put devices in SLOTB/SLOTC/SLOTD, will not get resource for those devices. and we can not go above to update SLOT A, because: some devices on SLOTB could already have driver loaded. if you don't like pciehp_realloc at this point, please only apply 1-8 and 11. Thanks Yinghai Lu -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
