[+cc Phillip] On Tue, Apr 30, 2013 at 9:19 PM, Robert Hancock <hancockrwd@xxxxxxxxx> wrote: > On 04/29/2013 10:47 PM, Bjorn Helgaas wrote: >> >> 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). > > > I would suspect that Windows' complaint about the BIOS mucking up the MTRRs > is likely the best hint. Likely Windows is detecting the problem and fixing > it up on resume, thus it only complains about "reduced resume performance". > If the MTRRs are messed up, then quite likely parts of RAM have become > uncacheable, causing performance to get randomly slaughtered in various > ways. > > From looking at the code it's not clear if we are checking/restoring the > MTRR contents after resume. If not, maybe we should be. I agree; the MTRR warning is a good hint. Artem? Phillip, I cc'd you because you have similar hardware and your https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1131468 report is slightly similar. Have you seen anything like this "reduced performance after resume" issue? If so, can you collect /proc/mtrr contents before and after suspending? Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
