On Wed, May 12, 2021 at 11:04 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, May 12, 2021 at 12:17:12PM +0800, Chris Chiu wrote: > > On Wed, May 12, 2021 at 12:30 AM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > 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. > > > > > But it's still in the `if (status)` branch so it will not get > > usb_set_device_state > > to USB_STATE_SUSPENDED, then usb_resume_both will not do the resume > > process for it. > > Ah, yes. I was mis-reading the patch. > > > My original thought is, we still take this as an abnormal status > > because we don't > > really know the reason for the timeout. Set reset_resume for the udev > > will make the > > kernel to reset_resume it. Or I have to create a new `goto` name in > > the `else` branch > > to force it back to the successful suspended process. And should I > > clean the status to > > zero for pm_runtime_put_sync()? What's your suggestion? > > For testing purposes, set status to 0 and jump to a new goto label in > the "else" branch. In other words, treat it as if the suspend really > had worked and go back to the successful pathway. Try this out and see > if it fixes the problem. > > If it does then the reset-resume isn't needed. If it doesn't, post your > patch again, and mention in the patch description that testing shows the > reset-resume really is necessary. > > Alan Stern Thanks for the suggestion. I revised the patch to create a new goto label in the "else" branch and clear the status to zero if the port is really suspended. It fixed the problem in my 100 time suspend/resume test. I will send v3 patch w/ the modification. Chris
