Re: PCI BAR1 Unassigned

From: Bjorn Helgaas
Date: Thu May 19 2011 - 18:39:11 EST

On Thu, May 19, 2011 at 4:20 PM, Jan Zwiegers <jan@xxxxxxxxxxxxxxxxxxxx> wrote:
> On 2011-05-20 12:13 AM, Bjorn Helgaas wrote:
>> On Thu, May 19, 2011 at 2:27 PM, Jan Zwiegers<jan@xxxxxxxxxxxxxxxxxxxx>
>>  wrote:
>>> On 2011-05-19 08:50 PM, Bjorn Helgaas wrote:
>>>> On Thu, May 19, 2011 at 10:28 AM, Jan Zwiegers<jan@xxxxxxxxxxxxxxxxxxxx>
>>>>  wrote:
>>>>> I have the problem below where my PCI card's second BAR does not get
>>>>> assigned.
>>>>> What can be the cause of this problem?
>>>>> The last kernel I tested on which worked OK was 2.6.27.
>>>>> My current problematic kernel 2.6.35.
>>>>> 05:01.0 Unassigned class [ff00]: Eagle Technology PCI-703 Analog I/O
>>>>> Card
>>>>> (rev 5c)
>>>>>    Flags: bus master, slow devsel, latency 32, IRQ 22
>>>>>    Memory at 93b00000 (type 3, prefetchable) [size=2K]
>>>>>    Memory at<unassigned>    (type 3, prefetchable)
>>>>>    Capabilities: [80] #00 [0600]
>>>>>    Kernel modules: pci703drv
>>>> Could be resource exhaustion or, more likely, we ran out because we
>>>> now assign resource to things that don't need them, leaving none for
>>>> things that *do* need them.  This sounds like a regression, so we
>>>> should open a bugzilla for it and attach dmesg logs from 2.6.27 and
>>>> 2.6.35.
>>>> Does this problem keep the driver from working?  (Sometimes drivers
>>>> don't actually use all the BARs a device supports.)
>>> I'm the maintainer of the driver and was involved in the development of
>>> the
>>> board as well in 2003. The board uses two BARS and the second BAR is the
>>> most important. The board worked fine since the 2.4 days and only
>>> recently
>>> became problematic. I suspect it works on even later kernels than 27,
>>> maybe
>>> 2.6.32.
>>> My knowledge is too little to actually determine if the problem is
>>> because
>>> the FPGA based PCI interface is not within spec or something that changed
>>> in
>>> the kernel, because of the post .30 releases becoming more strict to PCI
>>> specification, i.e. BIOS / Kernel interaction.
>> Well, let's at least look at the working and broken dmesg logs.  My
>> money is on kernel breakage.  If it used to work, it should still
>> work.
> What do you need from me? I have at least 3 machines on which it used to
> work and is now running a later kernel. I can post dmesg from both .27 and
> .35. Will do tomorrow when I'm back at the office.

Since you don't have continuous access to the machines, maybe you can
collect the /proc/iomem and "lspci -v" output at the same time you
collect the dmesg logs. That should be enough to get started.

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