On Wed, Dec 29, 2021 at 05:11:47PM +0800, Puma Hsu wrote:

On Wed, Dec 29, 2021 at 4:30 PM Greg KH [off-list ref] wrote:

quoted

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:

quoted

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.

Given that your product platform is an older kernel version than 5.17, I
think that you also want this in the older kernel releases, so please
mark it for stable backporting.

thanks,

greg k-h