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 19:15:12 +0800
From:	Yijing Wang <wangyijing@...wei.com>
To:	Chris Clayton <chris2553@...glemail.com>
CC:	Martin Mokrejs <mmokrejs@...d.natur.cuni.cz>,
	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

On 2013/1/28 19:01, Chris Clayton wrote:
> [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

Oh, should "pcie_ports=native" not "pciehp_ports=native".


>>> [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
> 
> 
> .
> 


-- 
Thanks!
Yijing

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