On Wed, Aug 07, 2013 at 01:05:40AM +0800, Alan Stern wrote: > On Wed, 7 Aug 2013, Huang Rui wrote: > > > > > Could you explain that how can you make sure the root cause is unable > > > > to relay wakup requests from downstream port to upstream port if > > > > downstream port's suspend feature is not set? The OS is unable wakeup > > > > from S3 at that time. We can't fetch dmesg log and serial port is > > > > suspend either at that time. Did you use any other tools to trace this > > > > issue? Could you teach me? Actually, I was encoutered this issue > > > > either. > > > > > > It was simple. I ran two tests. They were exactly the same, except > > > that the suspend feature was set in the first test and was not set in > > > the second test. Remote wakeup worked in the first test and not in the > > > second. > > > > > > > Got it, but I'm still a little confused. For example, one mouse is > > attached at usb2.0 port of roothub, and it supports remote wakeup. But > > the wakeup attribute is disabled for mouse defaultly, am I right? So > > Yes. > > > remote wakeup doesn't work on this mouse, then run system suspend into > > s3 with "global suspend"(don't send Set Suspend Feature request). In > > this case, remote wakeup and global suspend doesn't mix, am I right? > > No. In this case they do mix okay. > If use power button instead to wake up, is that mix? Or in other cases? > > But system still can not wake up normally. > > In this case, the system is not supposed to wake up when you press a > mouse button, because the mouse is disabled for remote wakeup. > Therefore the system behaves correctly. > I use "ehco enabled > /sys/usb/bus/.../power/wakeup" to enable USB Mouse remote wakeup, then sleep into S3. I found that wakeup attribute is clear to be disabled after resume. But if both USB Mouse and Keyboard are attached on usb3.0 port and keep usb2.0 port no attached, the wakeup attribute is remained. Could you kindly tell me why? > Instead of a mouse, consider a USB keyboard. Keyboards _are_ > enabled > for remote wakeup by default. And suppose the keyboard is plugged into > an external hub, not the root hub. > > Then pressing a key on the keyboard _should_ cause the system to wake > up from S3. But with some hubs, if you use global suspend then > pressing a key does not wake up the system. > Thank you. I got your meaning. Thanks, Rui -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
