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

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Date:	Mon, 1 Apr 2013 11:28:29 -0600
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	Chris Clayton <chris2553@...glemail.com>
Cc:	Martin Mokrejs <mmokrejs@...d.natur.cuni.cz>,
	Yijing Wang <wangyijing@...wei.com>,
	Yijing Wang <wangyijing0307@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: Re: 3.8.0-rc4+ - Oops on removing WinTV-HVR-1400 expresscard TV Tuner

On Tue, Mar 19, 2013 at 9:46 AM, Chris Clayton <chris2553@...glemail.com> wrote:
> Hi Bjorn,
>
> Sorry I meant to reply to your mail so that copy recipients will know the
> outcome of the things you asked me to do. But then I forgot. Doh! You should
> have received the attachment notification from bugzilla, I think.
>
>
> On 03/15/13 22:48, Bjorn Helgaas wrote:
>>
>> On Tue, Mar 12, 2013 at 4:20 PM, Bjorn Helgaas <bhelgaas@...gle.com>
>> wrote:
>>>
>>> On Sat, Mar 9, 2013 at 2:20 AM, Chris Clayton <chris2553@...glemail.com>
>>> wrote:
>>>>
>>>> On 03/08/13 22:57, Bjorn Helgaas wrote:
>>
>>
>>>>> Thanks.  I opened this bug report:
>>>>> https://bugzilla.kernel.org/show_bug.cgi?id=54981 to keep track of
>>>>> your logs.
>>
>>
>> Hi Chris,
>>
>> The current Linux acpiphp driver doesn't do anything unless it finds
>> devices with _EJ0 or _RMV methods, and your DSDT has neither.  But I
>> think that implementation is incorrect because I'm not convinced that
>> those methods are required in order to do hotplug via ACPI.  For
>> example, your DSDT *does* have an _L01 method that does notifications
>> to the root ports.  I suspect that hotplug events on your box generate
>> an SCI that invokes that method.  Linux basically ignores the
>> resulting notify events, and I suspect that hotplug works on Windows
>> because it is paying attention to them.
>>
>> Can you build a kernel with CONFIG_ACPI_DEBUG=y, do the following, and
>> attach all the output to the bugzilla?
>>
>> 1) Boot with empty ExpressCard slot (without using "pcie_ports=native")
>> 2) # echo 0x00010004 > /sys/module/acpi/parameters/debug_layer
>> 3) # echo 0x08000004 > /sys/module/acpi/parameters/debug_level
>> 4) # lspci -vv
>> 5) # setpci -s 1c.3 0x42.w
>> 6) # setpci -s 1c.3 0x5a.w
>> 7) # setpci -s 1c.3 0xd8.l
>> 8) Insert ExpressCard
>> 9) # setpci -s 1c.3 0x5a.w
>> 10) # dmesg
>>
>> Here's what I think we'll see:
>>
>> - Slot Implemented (bit 8 of XCAP at 0x42) set, indicating a slot is
>> implemented below this root port
>> - Hot Plug SCI Enable (bit 30 of MPC at 0xd8) set, indicating that the
>> root port should generate an SCI whenever a hotplug event is detected
>> - Presence Detect State (bit 6 of SLTSTS at 0x5a) change from 0 with
>> the slot empty to 1 with the slot occupied
>> - pciehp doing nothing (since _OSC didn't grant the OS permission to
>> use PCIe native hotplug)
>> - dmesg indication of the SCI, leading to a Bus Check notification to
>> \_SB.PCI0.RP04, which is the 1c.3 root port leading to the ExpressCard
>> slot
>>
>
> As far as I can see, your predicted outcomes where correct. I've added the
> logs to the bugzilla report.

Yes, it behaved exactly as I expected.  I attached a few more details
of the analysis to the bug report
(https://bugzilla.kernel.org/show_bug.cgi?id=54981).  I think we need
to rework acpiphp to fix this.  We will fix it, but I don't know who
will do it, or when it will happen.  My list is growing faster than I
can deal with :(

Thanks very much for your excellent data collection!

Bjorn
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