Hi Greg,
at 17:22, Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote:
at 22:17, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
I agree with Kai-Heng, this seems like a fairly light-weight solution
to a reasonable problem.
Thanks for your review.
As to the issue of how much it will slow down system shutdowns, I have
no idea. Probably not very much, unless somebody has an unusually
large number of USB devices plugged in, but only testing can give a
real answer.
In addition to that, only USB2 devices that enable LPM will slow down
shutdown process.
Right now only internally connected USB2 devices enable LPM, so the
numbers are even lower.
I suppose we could add an HCD flag for host controllers which require
this workaround. Either way, it's probably not a very big deal.
IMO this is not necessary. Only xHCI that reports hw_lpm_support will be
affected. At least for PC, this only became true after Whiskey Lake.
Kai-Heng
Alan Stern
This patch is included in Ubuntu’s kernel for a while now, and there’s no
regression report so far.
Please consider merge this patch.
Kai-Heng
