On Tue, May 11, 2021 at 01:04:36PM +0800, Chris Chiu wrote: > On Mon, May 10, 2021 at 11:02 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > > On Mon, May 10, 2021 at 10:50:29PM +0800, chris.chiu@xxxxxxxxxxxxx wrote: > > > From: Chris Chiu <chris.chiu@xxxxxxxxxxxxx> > > > > > > On the Realtek high-speed Hub(0bda:5487), the port which has wakeup > > > enabled_descendants will sometimes timeout when setting PORT_SUSPEND > > > feature. After checking the PORT_SUSPEND bit in wPortStatus, it is > > > already set. However, the hub will fail to activate because the > > > PORT_SUSPEND feature of that port is not cleared during resume. All > > > connected devices are lost after resume. > > > > > > This commit force reset-resume the device connected to the timeout > > > but suspended port so that the hub will have chance to clear the > > > PORT_SUSPEND feature during resume. > > > > Are you certain that the reset-resume is needed? What happens if you > > leave out the line that sets udev->reset_resume? The rest of the patch > > will cause the kernel to realize that the port really is suspended, so > > maybe the suspend feature will get cleared properly during resume. > > > > It's worthwhile to try the experiement and see what happens. > > > > Alan Stern > > > > If I leave out the udev->reset_resume set, the resume will fail. Please refer > to the following kernel log. The usb 1-1 is the hub which has wakeup enabled > descendants. > > [ 57.210472] usb 1-1: kworker/u32:7 timed out on ep0out len=0/0 > [ 57.211022] usb 1-1-port3: suspend timeout, status 0507 > [ 57.211130] hub 1-1:1.0: hub_suspend > [ 57.230500] usb 1-1: usb suspend, wakeup 0 > > The timeout happens at 57.210472 and you can see the PORT_SUSPEND > bit is actually set in the "status 0507". The following shows the resume log. > > [ 58.046556] usb 1-1: usb resume > [ 58.114515] usb 1-1: Waited 0ms for CONNECT > [ 58.114524] usb 1-1: finish resume > [ 58.114928] hub 1-1:1.0: hub_resume > [ 58.116035] usb 1-1-port3: status 0507 change 0000 > [ 58.116720] usb 1-1-port5: status 0503 change 0000 > [ 58.116778] hub 1-1.3:1.0: hub_resume > [ 58.116908] hub 1-1.3:1.0: hub_ext_port_status failed (err = -71) > [ 58.116952] usb 1-1.5: Waited 0ms for CONNECT > [ 58.116955] usb 1-1.5: finish resume > [ 58.117157] hub 1-1.3:1.0: hub_ext_port_status failed (err = -71) > [ 58.117397] usb 1-1.3-port5: can't resume, status -71 > [ 58.117782] hub 1-1.3:1.0: hub_ext_port_status failed (err = -71) > [ 58.118147] usb 1-1.3-port2: can't resume, status -71 > [ 58.118149] usb 1-1.3.2: Waited 0ms for CONNECT > [ 58.118151] usb 1-1.3-port2: status 07eb.906e after resume, -19 > [ 58.118153] usb 1-1.3.2: can't resume, status -19 > [ 58.118154] usb 1-1.3-port2: logical disconnect > [ 58.118526] usb 1-1.3-port2: cannot disable (err = -71) > > As you see in the 58.116035, the hub_resume and activate is OK for the > usb 1-1. The "usb 1-1.3: finish resume" is not in the log because it's not > considered suspended and no chance to ClearPortFeature. Wait -- why isn't it considered suspended? We saw at 57.211022 that 1-1-port3's Suspend feature really was set, and thanks to your patch, the kernel should now believe that the port is suspended. > Then it fails > the subsequent hub 1-1.3 resume and active because the usb 1-1.3 happens > to be a downstream hub. So this is why we need at least udev->reset_resume > to give this kind of timeout port/device a chance to clear port feature and > come back from an unknown state. Don't worry about this part. Naturally anything associated with the 1-1.3 hub will fail after the resume of 1-1-port3 is messed up. Fix the first problem (failure to resume the port) and the second problem is likely to go away. Alan Stern
