linux-kernel - Re: PCIe can not rescan for new PCIe device ( FPGA board )

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Date:	Mon, 24 Oct 2011 14:00:02 +0900
From:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
To:	Abdelghani Ouchabane <abdelghani@...no.com>
CC:	Bjorn Helgaas <bhelgaas@...gle.com>, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org
Subject: Re: PCIe can not rescan for new PCIe device ( FPGA board )

Hello,

I'm sorry for the long delay.

(2011/10/14 18:40), Abdelghani Ouchabane wrote:
> On 13/10/11 14:50, Kenji Kaneshige wrote:
>> Thank you for the information. Though I don't have any good news for you,
>> I think as follows based on the info.
>>
>> - There are two hot-plug capable PCIe slots on your machine.
>>
>> - But, it seems you are using fakephp driver, not pciehp (is that
>>    correct?). The fakephp cannot handle hot-plug event such as presence
>>    change event on the slot. This is why the bus is not scanned automatically.
>>
>> - Unfortunately, the bus would not be scanned automatically even if you
>>    use pciehp. As I told you in the previous email, current pciehp don't
>>    scan the bus automatically only if the slot is hot-plug surprise
>>    capable. According to the lspci output, your hotplug controller is not
>>    hot-plug surprise capable.
>>
>> - I don't think pciehp solve invalid register read problem. According to
>>    the lspci output, power controller capability isn't present on your
>>    hotplug controller. On such environment, pciehp driver does almost the
>>    same thing as fakephp does (just scan the bus/remove the pci device data
>>    structure) except hot-plug event handling.
>>
>> But it's worth whole trying pciehp.
>> By the way, have you tried acpiphp? It might help you.
>>
>> Regards,
>> Kenji Kaneshige
>>
> 
> Hallo Kenji,
> 
> many thanks for your great supports. The new BIOS from Congatec solves
> the problem.
> 
> I using both fakephp&  pciehp drivers, Can I use both drivers at the
> same time?

I think, "no".

> I am using fakephp because I need "/sys/bus/pci/slots/0000\:02\:00.0/power".
> 
> Other thing: my Kernel has "CONFIG_ACPI_PROC_EVENT is not set", does
> this explain why the scan is not performed automatically?

Fakephp driver doesn't have any corresponding hotplug controller (hardware).
So I don't think there is no way to detect presence change event on the slot.

> 
> [root@...alhost ~]# modprobe acpiphp
> FATAL: Error inserting acpiphp
> (/lib/modules/2.6.40.3-0.119.delos.i686/kernel/drivers/pci/hotplug/acpiphp.ko):
> No such device
> 
> What is the advantage to use acpiphp ?

Some platform only allows acpiphp, but doesn't allow PCIe native hotplug driver
(like pciehp). The 'pciehp_force' specified your environment is to load pciehp
forcibly on such platform. So I thought acpiphp might solve your problem.

Regards,
Kenji Kaneshige



> 
> 
> Cheers,
> Ghani
> 
> 
> 
> 
> 
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