Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx> writes:
> Eric W. Biederman wrote:
>> Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx> writes:
>>
>>> Eric W. Biederman wrote:
>>>> In general a BIOS may goof or we may hotplug in a hotplug controller.
>>>> In either case the kernel needs to reserve resources for plugging
>>>> in more devices in the future instead of creating a minimal resource
>>>> assignment.
>>>>
>>> I think we would need the same mechanism also for PCI bus number
>>> assignment so that we can hot-plug devices containing bridges on
>>> the leaf hot-plug slots.
>>
>> Yep that would be handy. I haven't had that case come up as a problem
>> yet.
>>
>>> (snip.)
>>>
>>>> /**
>>>> * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children
>>>> * @bus: pointer to PCI bus structure to search
>>>> @@ -2672,6 +2678,10 @@ static int __init pci_setup(char *str)
>>>> strlen(str + 19));
>>>> } else if (!strncmp(str, "ecrc=", 5)) {
>>>> pcie_ecrc_get_policy(str + 5);
>>>> + } else if (!strncmp(str, "hpiosize=", 9)) {
>>>> + pci_hotplug_io_size = memparse(str + 9, &str);
>>>> + } else if (!strncmp(str, "hpmemsize=", 10)) {
>>>> + pci_hotplug_mem_size = memparse(str + 10, &str);
>>>> } else {
>>>> printk(KERN_ERR "PCI: Unknown option `%s'\n",
>>>> str);
>>> I think it would be better if we can specify the size per hotplug
>>> controller driver or per slot or etc.
>>
>> This happens too early to do anything per driver as this all happens
>> before the hotplug drivers load. A per slot override seems reasonable
>> but I am starting with the simplest case an override of the default
>> allocation.
>
> Do you need to override the resource assignments by firmware
> at boot time?
That has come up. Unfortunately the kernel didn't know that hardware
platform well enough to assign the resources correctly. So I had to
go back in and fix the firmware.
I more commonly plug in pcie hotplug bridges into my pcie hotplug
bridges, and long before I can load a driver on them I need to assign
resources.
Eric
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