linux-kernel - Re: 3.8.0-rc4+ - Oops on removing WinTV-HVR-1400 expresscard TV Tuner

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Date:	Mon, 28 Jan 2013 11:01:56 +0000
From:	Chris Clayton <chris2553@...glemail.com>
To:	Martin Mokrejs <mmokrejs@...d.natur.cuni.cz>
CC:	Yijing Wang <wangyijing@...wei.com>,
	Yijing Wang <wangyijing0307@...il.com>,
	LKML <linux-kernel@...r.kernel.org>, linux-pci@...r.kernel.org
Subject: Re: 3.8.0-rc4+ - Oops on removing WinTV-HVR-1400 expresscard TV Tuner

[no one screamed, so linux-media ml dropped]

Hi Martin,

On 01/28/13 10:56, Martin Mokrejs wrote:
>
>
> Chris Clayton wrote:
>> Hi Yijing,
>>
>> On 01/28/13 02:40, Yijing Wang wrote:
>>> Hi Chris,
>>>      Sorry for the delay reply. It seems like my reply last night was missed.
>>>
>>>   From the sysinfo you provide, there are no pcie port devices under /sys/bus/pci_express/devices.
>>> Maybe because there are some problems with _OSC in your laptop, so pcie port driver won't create pcie port device
>>> for hotplug, aer and so on.
>>>
>>> Maybe you can add boot parameter "pcie_ports=native" and reboot your laptop.
>>> Then use #modprobe pciehp pciehp_force=1 pciehp_debug=1 to load pciehp modules.
>>> After above actions, enter /sys/bus/pci_express/devices/ directory and /sys/bus/pci/slots/
>>> Some slots and pcie port devices should be there now.
>>>
>> Sorry, I've tried your suggestion, but the two directories are still empty.
>>
>> I verified the test environment as follows:
>>
>> [chris:~]$ uname -a
>> Linux laptop 3.7.4 #15 SMP PREEMPT Mon Jan 28 09:43:57 GMT 2013 i686 GNU/Linux
>> [chris:~]$ grep acpiphp /boot/System.map-3.7.4
>> [chris:~]$ modinfo acpiphp
>> modinfo: ERROR: Module acpiphp not found.
>> [chris:~]$ modinfo pciehp
>> filename:       /lib/modules/3.7.4/kernel/drivers/pci/hotplug/pciehp.ko
>> license:        GPL
>> description:    PCI Express Hot Plug Controller Driver
>> author:         Dan Zink <dan.zink@...paq.com>, Greg Kroah-Hartman <greg@...ah.com>, Dely Sy <dely.l.sy@...el.com>
>> depends:
>> intree:         Y
>> vermagic:       3.7.4 SMP preempt mod_unload CORE2
>> parm:           pciehp_detect_mode:Slot detection mode: pcie, acpi, auto
>>    pcie          - Use PCIe based slot detection
>>    acpi          - Use ACPI for slot detection
>>    auto(default) - Auto select mode. Use acpi option if duplicate
>>                    slot ids are found. Otherwise, use pcie option
>>   (charp)
>> parm:           pciehp_debug:Debugging mode enabled or not (bool)
>> parm:           pciehp_poll_mode:Using polling mechanism for hot-plug events or not (bool)
>> parm:           pciehp_poll_time:Polling mechanism frequency, in seconds (int)
>> parm:           pciehp_force:Force pciehp, even if OSHP is missing (bool)
>> [chris:~]$ cat /proc/cmdline
>> root=/dev/sda5 pciehp_ports=native ro resume=/dev/sda6
>> [chris:~]$ sudo modprobe pciehp pciehp_force=1 pciehp_debug=1
>> [chris:~]$ lsmod
>> Module                  Size  Used by
>> pciehp                 19907  0
>> [...]
>>
>> You will notice that the kernel I have used is 3.7.4. I hope that's a suitable kernel for your tests. I've moved away from the 3.8 development kernel onto one that's stable and on which Martin has identified a solution. I see Greg KH released 3.7.5 yesterday and it includes a pciehp change. I'll upgrade to that, run the tests again and report back.
>>
>> One question - should I include the (acpi) pci_slot driver in the kernel build or does pciehp populate the directories without pci_slot?
>
> Hi Chris,
>    I am not a kernel developer but from the other threads at linux-pci I gathered there are in some
> scenarios problems with improper loading of the hotplug modules. Therefore, the patches floating
> now around are to disable hotplug module availability. Therefore, I suggested you to try only
> only static kernel support for hotplug. That way you don't hit the issue. That is for sure not
> addressed in 3.7.5, seems that it is probably in -next.
> Martin
>
In a few minutes I'll be sending out another reply to Yijing's 
suggestions because I noticed a typo in the parameter I added to the 
kernel command line. I'm now going back through email to remember why we 
were trying to get those /sys/bus/pci... directories populated.

Watch this space! :-)
Chris

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