Hi,Greg Thanks. Yes, the suspending takes very litte time. But the time ,which the suspending takes, has something to do with the hardware. Especially when you using an old mechanical hard disk or something like that. how do you know you are hitting the key "during" the suspend? And after notice the problem, I do some hack to confirm that it have to be during the suspending process: Within funcion kernel/power/suspend.c (4.9 version kernel source) static int suspend_enter(suspend_state_t state, bool *wakeup), I added a line code mdelay(5000); just before error = platform_suspend_prepare_late(state); to increase the time window. Then rebuild&install the kernel. After the new kernel runs up, now much easier (we got about 5 seconds more) to reproduce the bug. Thanks for your time. Jim From: Greg KH Date: 2017-08-31 15:16 To: jingyun@cpu-os.ac.cn CC: kernelnewbies Subject: Re: Re: USB keyboard can NOT wakeup from S3( suspend to RAM ) On Thu, Aug 31, 2017 at 06:38:48AM +0800, jingyun@cpu-os.ac.cn wrote:
Hi, Greg
Thanks for your time. First of all, if I do NOT hit the keyboard during the suspend. Then my keyboard CAN wake the system up from suspend. This has rule out that my system does NOT support USB wakeup. Right ?
I really do not know, sorry. Given taht suspend to ram go so fast, how do you know you are hitting the key "during" the suspend? It's an almost instantaneous process. Check your bios settings about this, or, just don't touch the keyboard until you really do want to wake it up :) good luck! greg k-h