Re: Abysmal HDD/USB write speed after sleep on a UEFI system

["Artem S. Tashkinov" <t.artem@lycos.com>]

May 8, 2013 04:25:43 AM, Patrik Jakobsson wrote:
On Wed, May 8, 2013 at 12:02 AM, Bjorn Helgaas wrote:
>> On Tue, May 7, 2013 at 2:48 PM, Patrik Jakobsson wrote:
>>> On Tue, May 7, 2013 at 10:20 PM, Bjorn Helgaas  wrote:
>>>>> I'm not sure if reading /proc/mtrr actually reads the registers out of
>>>>> the CPU each time, or whether we just return the cached values we read
>>>>> out during initial boot-up. If the latter, then this output isn't
>>>>> really useful as there's no guarantee the values are still intact.
>>>>
>>>> Good point.  From what I can tell, on Artem's system with "CPU0:
>>>> Intel(R) Core(TM) i5-2500 CPU @ 3.30GHz," we would be using
>>>> generic_mtrr_ops, and generic_get_mtrr() appears to read from the
>>>> MSRs, so I think it should be useful.
>>>
>>> FWIW, that motherboard suffers from a PCI to PCIE bridge problem. It might
>>> have been fixed by bios upgrades by now but not sure.
>>>
>>> It might also suffer (depending on the revision) from the Sandy bridge SATA
>>> issue. So if affected, SATA controller is a ticking bomb.
>>>
>>> I have a P8H67-V motherboard but I haven't seen any suspend related issues.
>>>
>>> If this is totally unrelated I'm sorry for wasting your time. Just thought it
>>> might be good to know.
>>
>> Thanks for chiming in.  I'm not familiar with either of the issues you
>> mentioned.  Do you have any references where I could read up on them?
>
>I think this is the official statement from Intel on the SATA issue:
>http://newsroom.intel.com/community/intel_newsroom/blog/2011/01/31/intel-identifies-chipset-design-error-implementing-solution

My motherboard has a new fixed B3 revision so this issue doesn't affect me.
Besides this SATA ports degradation issue is constantly present - it has no
relationship to suspend.

>
>And here's a link to a discussion about the PCIe-to-PCI bridge stuff:
>https://lkml.org/lkml/2012/1/30/216
>
>> Artem's system has a PCIe-to-PCI bridge (not a PCI-to-PCIe bridge) at
>> 05:00.0, but it leads to [bus 06] and there's nothing on bus 06, so I
>> don't think that's the problem.
>
>I meant what you said ;) and yes, it seems unrelated. Both my P8H67 and a
>P8P67 I've built behave nicely if nothing is connected.

Have you tried suspending more than three times? In the absence of UEFI
boot this bug emerges only on a third or even fourth resume attempt. UEFI
boot triggers it immediately on a first resume though.

>> And the issue affects both USB and a hard drive, so I suspect it's
>> more than just SATA.  Artem, did you identify the PCI devices leading
>> to your USB and hard drive?  I can't remember if I've actually seen
>> that.