linux-kernel - Re: [char-misc 3.11 V2] mei: me: fix hardware reset flow

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Date:	Tue, 30 Jul 2013 19:04:41 +0000
From:	Shuah Khan <shuah.kh@...sung.com>
To:	"Winkler, Tomas" <tomas.winkler@...el.com>
Cc:	Greg KH <gregkh@...uxfoundation.org>,
	"arnd@...db.de" <arnd@...db.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Konstantin Khlebnikov <khlebnikov@...nvz.org>,
	Shuah Khan <shuah.kh@...sung.com>
Subject: Re: [char-misc 3.11 V2] mei: me: fix hardware reset flow

On 07/30/2013 08:29 AM, Winkler, Tomas wrote:
>
>> Subject: Re: [char-misc 3.11 V2] mei: me: fix hardware reset flow
>>
>> On Tue, Jul 30, 2013 at 02:11:51PM +0300, Tomas Winkler wrote:
>>> Both H_IS and H_IE needs to be set to receive H_RDY interrupt
>>>
>>> 1. Assert H_IS to clear the interrupts during hw reset and use
>>> mei_me_reg_write instead of mei_hcsr_set as the later strips down the
>>> H_IS
>>>
>>> 2. fix interrupt disablement embarrassing typo
>>>    hcsr |= ~H_IE -> hcsr &= ~H_IE;
>>> this will remove the unwanted interrupt on power down
>>>
>>> 3. remove useless debug print outs
>>>
>>> Cc: Shuah Khan <shuah.kh@...sung.com>
>>> Cc: Konstantin Khlebnikov <khlebnikov@...nvz.org>
>>> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
>>> ---
>>>
>>> V2: Fixed typo in Shuah email
>>>
>>> Hope this finally resolve the ME reset issue for all
>>
>> Can I get a "Tested-by:" from someone to ensure that it really does solve the
>> problem?
>
> Yes,  please wait for ack/test results. It works for me but unfortunately I cannot go over all  9 gens of  PCH and all their proliferations  where ME resides.
> I'm putting some effort to have better legacy HW testing coverage but I'm not there yet.
>

Tomas,

I have a test system that has shows the mei_me reset problem after 
boot-up. I tested this patch on top of 3.11-rc3 that has the previous 4 
patches. I am seeing the issue still on this system:

00:03.0 Communication controller: Intel Corporation 82Q963/Q965 HECI 
Controller (rev 02)
         Subsystem: Hewlett-Packard Company Device 2801
         Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- 
ParErr- Stepping- SERR- FastB2B- DisINTx+
         Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- 
<TAbort- <MAbort- >SERR- <PERR- INTx-
         Latency: 0
         Interrupt: pin A routed to IRQ 41
         Region 0: Memory at f0521900 (64-bit, non-prefetchable) [size=16]
         Capabilities: <access denied>
         Kernel driver in use: mei_me


I am attaching the dmesg. Please let me know if you need any more 
information from the system.

-- Shuah

Shuah Khan, Linux Kernel Developer - Open Source Group Samsung Research 
America (Silicon Valley) shuah.kh@...sung.com | (970) 672-0658

View attachment "dmesg_3.11_rc3_with_fix" of type "text/plain" (43883 bytes)