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

[Bjorn Helgaas]

On Sat, Apr 27, 2013 at 4:10 AM, Artem S. Tashkinov <t.artem@xxxxxxxxx> wrote:
>>
>>Did this problem ever get resolved?
>>
>
> Hello,
>
> Unfortunately, no. Out of curiosity I've tried booting kernel
> 3.9-rc8 in EUFI mode but it exhibits the same problem.
>
> Right after the boot:
>
> [root@localhost ~]# dd if=/dev/zero of=test bs=64M count=3
> 3+0 records in
> 3+0 records out
> 201326592 bytes (201 MB) copied, 1.08544 s, 185 MB/s
>
> After suspend/resume:
>
> # dd if=/dev/zero of=test bs=64M count=3
> 3+0 records in
> 3+0 records out
> 201326592 bytes (201 MB) copied, 66.5392 s, 3.0 MB/s
>
> That's for my primary SATA-3 HDD.
>
> Forgive me my impudence but I believe debugging the USB stack is
> tangential to this problem. Something far deeper than USB support
> breaks, but so far no one has come even with the slightest clue of
> what that might be.

I tend to agree that it sounds like something deeper than USB is
broken.  I admit I'm just grasping at straws because I don't have any
good ideas yet.

Here are three easy things you can try:

1) Collect "lspci -vvv -xxxx" output before and after the
suspend/resume to investigate the XHCI Unsupported Request errors.

2) Collect the contents of /proc/mtrr before and after the suspend/resume.

3) After the suspend/resume, try the "setpci" to set the MSI address
back to the original value to see if it makes a difference (see my Feb
12 message).

Bjorn
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