On Sat, Feb 03, 2018 at 07:25:54PM +0100, Markus Demleitner wrote: > On Tue, Jan 30, 2018 at 07:32:04AM +0100, Greg KH wrote: > > On Mon, Jan 29, 2018 at 07:21:09PM +0100, Markus Demleitner wrote: > > > A while ago I opened bug #197863 in the kernel bugzilla: > > > > > > https://bugzilla.kernel.org/show_bug.cgi?id=197863 > > > > > > Essentially, xhci_hcd on a resume from RAM takes several seconds on a > > > Thinkpad X240 that is equipped with a Sierra LTE modem after an > > > upgrade to 4.13: > [...] > > > Now, interestingly, there are quick resumes in 4.15.0, too, now and > > > then. In that case, things look pretty much like on 4.12.2. Here's > > > a 4.15.0 fast resume example: > > > > > > [ 873.127570] usb 1-4: device firmware changed > > > [ 873.277351] usb 1-8: reset high-speed USB device number 4 using xhci_hcd > > > [ 873.515141] restoring control 00000000-0000-0000-0000-000000000101/0/2 > > > [ 873.583238] OOM killer enabled. > > > [ 873.583240] Restarting tasks ... > > > [ 873.583339] usb 1-4: USB disconnect, device number 10 > > > [ 873.586356] done. > > > [ 873.604420] PM: suspend exit > > > [ 873.737283] usb 1-4: new high-speed USB device number 11 using xhci_hcd > > > [ 880.867398] usb 1-4: device descriptor read/64, error -110 > > > [ 881.175558] usb 1-4: New USB device found, idVendor=1199, idProduct=a001 > > > [ 881.175563] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 > > > [ 881.175566] usb 1-4: Product: Sierra Wireless EM7345 4G LTE > > > [ 881.175568] usb 1-4: Manufacturer: Sierra Wireless Inc. > > > [ 881.175570] usb 1-4: SerialNumber: 013937002544516 > > > > > > Any guess what might be behind this? > > > > Any chance you can run 'git bisect' to find the offending commit for > > this issue? > > It's 662591461c4b9a1e3b9b159dbf37648a585ebaae. To my eyes, it even > looks plausible that it's causing the problematic behaviour, but > since I can't say I understand what I'd be doing if I dabbled with > the change, I've refrained from guessing how to fix it. > > I'm happy to try patches, though. Ok, thanks. I've added the authors of this patch to the email here, perhaps they have an idea of what is going on? greg k-h