linux-kernel - Re: Q: state of pci express hotplug

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Date:	Wed, 4 Feb 2009 16:49:49 -0700
From:	Alex Chiang <achiang@...com>
To:	Krishna Kothapalli <krishna_sunitha@...mail.com>
Cc:	kaneshige.kenji@...fujitsu.com, ebiederm@...ssion.com,
	linux-pci@...r.kernel.org, jbarnes@...tuousgeek.org,
	djwong@...ibm.com, xyzzy@...akeasy.org,
	linux-kernel@...r.kernel.org
Subject: Re: Q: state of pci express hotplug

* Krishna Kothapalli <krishna_sunitha@...mail.com>:
> 
> > o The pciehp's debug output. We can get this as follows.
>   # /sbin/modprobe pciehp pciehp_debug
>   # dmesg | grep pciehp 
> pciehp 0000:00:09.0:pcie02: Hotplug Controller:
> pciehp 0000:00:09.0:pcie02:   Seg/Bus/Dev/Func/IRQ : 0000:00:09.0 IRQ 2295
> pciehp 0000:00:09.0:pcie02:   Vendor ID            : 0x8086
> pciehp 0000:00:09.0:pcie02:   Device ID            : 0x3410
> pciehp 0000:00:09.0:pcie02:   Subsystem ID         : 0x0000
> pciehp 0000:00:09.0:pcie02:   Subsystem Vendor ID  : 0x0000
> pciehp 0000:00:09.0:pcie02:   PCIe Cap offset      : 0x90
> pciehp 0000:00:09.0:pcie02: Slot Capabilities      : 0x0302005f
> pciehp 0000:00:09.0:pcie02:   Physical Slot Number : 96

Hm, this is merely an observation, but the slot number here seems
wacky compared to the one that acpiphp reports later below.

Did we ever get a dmidecode from this machine?

Also, once you insert the card, what happens if you:

	# echo 1 > /sys/bus/pci/slots/96/power

Does that do anything?

> [root@...alhost test]#  /sbin/modprobe acpiphp debug
> [root@...alhost test]# dmesg | grep acpiphp
> acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5
> acpiphp_glue: found PCI-to-PCI bridge at PCI 0000:00:09.0
> acpiphp_glue: found ACPI PCI Hotplug slot 2 at PCI 0000:09:00
> acpiphp: Slot [2] registered

Here we see that ACPI thinks it's slot 2, not 96.

> acpiphp_glue: Bus 0000:09 has 1 slot
> acpiphp_glue: Total 1 slots
> [root@...alhost test]# 
> [root@...alhost test]# ls -lt /sys/bus/pci/slots
> total 0
> drwxr-xr-x 2 root root 0 2009-02-04 09:59 2
> ---  Insert PCI express card in the slot
> [root@...alhost test]# dmesg | grep acpiphp
> [root@...alhost test]# lspci | wc
>     105    1284    9203
> [root@...alhost test]# ls -lt /sys/bus/pci/slots/2/
> total 0
> -r--r--r-- 1 root root 4096 2009-02-04 10:01 adapter
> -r--r--r-- 1 root root 4096 2009-02-04 10:01 address
> -rw-r--r-- 1 root root 4096 2009-02-04 10:01 attention
> -r--r--r-- 1 root root 4096 2009-02-04 10:01 latch
> -rw-r--r-- 1 root root 4096 2009-02-04 10:01 power

Can you echo a 1 into the power file above?

> [root@...alhost test]# 
> [root@...alhost test]# /sbin/rmmod acpiphp
> [root@...alhost test]# dmesg | grep acpiphp
> acpiphp: Slot [2] unregistered
> acpiphp: release_slot - physical_slot = 2
> [root@...alhost test]# 

Thanks.

/ac

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