Re: ATA failure regression in kernel 4.2

[Jiang Liu <jiang.liu@linux.intel.com>]

On 2015/7/27 23:21, Alex Deucher wrote:
> On Sun, Jul 26, 2015 at 11:01 PM, Jiang Liu <jiang.liu@linux.intel.com> wrote:
>> On 2015/7/25 1:38, Alex Deucher wrote:
>>> On Thu, Jul 23, 2015 at 2:44 PM, Alex Deucher <alexdeucher@gmail.com> wrote:
>>>> On Thu, Jul 23, 2015 at 2:35 PM, Tejun Heo <tj@kernel.org> wrote:
>>>>> Hello,
>>>>>
>>>>> On Thu, Jul 23, 2015 at 01:48:24PM -0400, Alex Deucher wrote:
>>>>>> Something new in kernel 4.2 seems to have broken one of my hard drives
>>>>>> (ssd) in kernel 4.2.  4.1 and older kernels work fine.  Here are the
>>>>>> relevant logs.
>>>>>>
>>>>> ...
>>>>>> [    6.547628] ata2.00: qc timeout (cmd 0xec)
>>>>>> [    6.547721] ata2.00: failed to IDENTIFY (I/O error, err_mask=0x4)
>>>>>> [    7.007213] ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
>>>>>> [   16.997819] ata2.00: qc timeout (cmd 0xec)
>>>>>> [   16.997910] ata2.00: failed to IDENTIFY (I/O error, err_mask=0x4)
>>>>>> [   16.997995] ata2: limiting SATA link speed to 3.0 Gbps
>>>>>> [   17.457400] ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 320)
>>>>>> [   47.429257] ata2.00: qc timeout (cmd 0xec)
>>>>>> [   47.429349] ata2.00: failed to IDENTIFY (I/O error, err_mask=0x4)
>>>>>> [   47.888822] ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 320)
>>>>>
>>>>> Nothing really rings a bell.  Timeouts on IDENTIFY.  Could be IRQ
>>>>> related.  Which controller is it (lspci -nn)?  Also, can you try to
>>>>> bisect the issue?
>>>>
>>>> 00:11.0 SATA controller [0106]: Advanced Micro Devices, Inc. [AMD] FCH
>>>> SATA Controller [AHCI mode] [1022:7801] (rev 40)
>>>> 00:14.1 IDE interface [0101]: Advanced Micro Devices, Inc. [AMD] FCH
>>>> IDE Controller [1022:780c]
>>>>
>>>> I can take a look at bisecting later this week.
>>>
>>> You were right about the interrupts.  This is an AMD Kaveri APU system.
>> Hi Alex,
>>         Could you please help to provide more information about the
>> system so we could identify the issue? Dmesg and /proc/interrupts
>> from good and bad kernels are welcomed.
>> Thanks!
>> Gerry
> 
> See attached.  Thanks!
Hi Alex,
	Thanks for the info. Seems something is wrong with multiple-MSI
support. To narrow down the scope, could you please help to:
1) apply the small patch and retest
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 7e62751abfac..35f524cc23b7 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1345,6 +1345,7 @@ static int ahci_init_msi(struct pci_dev *pdev,
unsigned int n_ports,
        if (nvec < 0)
                return nvec;

+       nvec = 1;
        /*
         * If number of MSIs is less than number of ports then Sharing Last
         * Message mode could be enforced. In this case assume that
advantage
2) Disable interrupt remapping by kernel parameter "nointremap"
and retest.
Thanks!
Gerry