Hi Alan, > From: Alan Stern, Sent: Wednesday, January 22, 2020 11:59 PM > > On Wed, 22 Jan 2020, Yoshihiro Shimoda wrote: > > > > Okay, now I understand. I misread the code in the original patch. > > > But now it looks like the code does roughly this: > > > > > > Timer routine: if (ehci_platform_quirk_poll_check_condition(ehci)) > > > schedule_work(); > > > > > > Work routine: usleep_range(4000, 8000); > > > udelay(10); > > > if (!ehci_platform_quirk_poll_check_condition(ehci)) > > > return; > > > udelay(10); > > > if (!ehci_platform_quirk_poll_check_condition(ehci)) > > > return; > > > ehci_platform_quirk_poll_rebind_companion(ehci); > > > > > > So there are three calls to quirk_poll_check_condition, with 4 - 8 ms > > > between the first and second, and 10 us between the second and third. > > > Do you really need to have this combination of a long delay followed by > > > a short delay? Wouldn't two check_condition calls with only one delay > > > be good enough? > > > > I had implemented this code by using hardware team's suggestion without > > any doubt. So, I asked hardware team about this combination of delays. > > The hardware team said this combination can reduce misdetection ratio > > from noise and so on. They also said we can wait single 5 ms instead > > this combination (but this cannot reduce misdetection ratio). > > Sure, the more times you delay and recheck, the better the error rate. > But you don't want to go too far. You're correct. However, my mind is changed a little... I would like to remain rechecking as the same as before. > > So, now I'm thinking that the following process (single wait) is > > enough and it can improve readability. But, what do you think? > > > > Timer routine: if (ehci_platform_quirk_poll_check_condition(ehci)) > > schedule_delayed_work(5 ms); > > > > Delayed work routine: > > if (!ehci_platform_quirk_poll_check_condition(ehci)) > > return; > > ehci_platform_quirk_poll_rebind_companion(ehci); > > That looks good to me. Thank you for your feedback! I'll submit v2 patch soon. Best regards, Yoshihiro Shimoda > Alan Stern
