Re: [PATCH] xhci: re-initialize the HC during resume if HCE was set

From: Greg KH
Date: Wed Dec 29 2021 - 03:30:30 EST


A: http://en.wikipedia.org/wiki/Top_post
Q: Were do I find info about this thing called top-posting?
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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?

thanks,

greg k-h