On Wed, Dec 29, 2021 at 4:30 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > A: http://en.wikipedia.org/wiki/Top_post > Q: Were do I find info about this thing called top-posting? > A: Because it messes up the order in which people normally read text. > Q: Why is top-posting such a bad thing? > A: Top-posting. > Q: What is the most annoying thing in e-mail? > > A: No. > Q: Should I include quotations after my reply? > > http://daringfireball.net/2007/07/on_top > > On Wed, Dec 29, 2021 at 01:53:04PM +0800, Puma Hsu wrote: > > This commit is not used to fix a specific commit. We find a condition > > that when XHCI runs the resume process but the HCE flag is set, then > > the Run/Stop bit of USBCMD cannot be set so that HC would not be > > enabled. In fact, HC may already meet a problem at this moment. > > Besides, in xHCI requirements specification revision 1.2, Table 5-21 > > BIT(12) claims that Software should re-initialize the xHC when HCE is > > set. Therefore, I think this commit could be the error handling for > > HCE. > > So this does not actually fix an issue that you have seen in any device > or testing? So it is not relevant for older kernels but just "nice to > have"? > > How did you test this if you can not duplicate the problem? > Yes, we actually see that the HCE may be detected while running xhci_resume on our product platform, so I'm able to verify this commit can fix such a condition. For older kernels, I'm not sure whether someone had ever met such issue, but I believe the Run/Stop bit of USBCMD cannot be set once HCE is raised. Thanks. Puma Hsu > thanks, > > greg k-h
