Hi, On Wed, May 07, 2014 at 12:59:39PM -0500, Felipe Balbi wrote: > On Wed, May 07, 2014 at 01:37:29PM -0400, Alan Stern wrote: > > On Wed, 7 May 2014, Felipe Balbi wrote: > > > > > > I think these patches could be related: > > > > > > > > commit 25cd2882e2fc8bd8ed7acaee0ec979f11feda6d7 > > > > usb/xhci: Change how we indicate a host supports Link PM. > > > > > > > > commit 140e3026a57ab7d830dab2f2c57796c222db0ea9 > > > > Revert "usbcore: set lpm_capable field for LPM capable root hubs" > > > > > > > > Both of them are added after 3.13, and do additional checking before setting > > > > udev->lpm_capable > > > > > > last commit could be broken, looking at my root hub's BOS desc I get: > > > > > > bU1DevExitLat 10 micro seconds > > > bU2DevExitLat 512 micro seconds > > > > > > Likewise on the device that I'm connecting to that root hub: > > > > > > bU1DevExitLat 1 micro seconds > > > bU2DevExitLat 500 micro seconds > > > > > > So it should be enabled, and yet I see on dmesg: > > > > > > [ 10.329092] usb 2-2.1.1: LPM exit latency is zeroed, disabling LPM. > > > > 2-2.1.1 is _not_ connected to that root hub. There are two other hubs > > in between. Which means this problem has nothing to do with how LPM is > > determined for root hubs. > > good point. this means that all my front facing USB3 ports are going > through two hubs! Oh well, I'll go try every port on my desktop to > see if I find a roothub port. ok, so I've spent the last few days trying to get this to work but I can't see lpm_capable *ever* being set for any of my roothub ports. I've attached my device to the roothub port directly but, as the roothub isn't marked as lpm_capable, none of its children will be. I think commit 25cd2882e2fc8bd8ed7acaee0ec979f11feda6d7 isn't perfect in that regard, but partially reverting that doesn't help either. I'm now pretty busy with internal stuff right now and won't be able to work on this for a while, but I'll get back to it after merge window. Meanwhile, if someone finds a fix for the (possible) bug, I'd be able to test. cheers -- balbi
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