A: No. Q: Should I include quotations after my reply? http://daringfireball.net/2007/07/on_top
On Wed, Jan 08, 2014 at 03:49:07AM +0000, Tang, Jianqiang wrote: > Hi, > 1) I met this issue one time just boot up our Linux Platform(Kernel3.10) > with XHCI driver, then kernel panic happen. > > And this issue reported once by other internal team. > > Nothing special of reproduce step and do not need special Hardware I think. > > Just random issue which will happen when meet the timing condition. > > 2) This issue is introduced by this patch: > > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=596d789a211d134dc5f94d1e5957248c204ef850 > > which set all hub autosuspend delay to 0. That patch was released in a kernel almost a full year ago, yet we have never had a report of this happening before, so are you sure this patch is the root cause? > This causes race condition during XHCI driver initialization, > > After USB2 hcd and USB2 root hub finish the initialization, USB2 root hub > is functional and auto suspend right now, hence trigger XHCI runtime suspend > flow; > > At the same time, XHCI driver continue to initialize the USB3 hcd and > assign to xhci->shared_hcd after finish the initialization; > > Since xhci_suspend() use the xhci->shared_hcd, so there is race condition > that when XHCI runtime suspend called, xhci->shared_hcd still NULL. > > I think this patch is a fix solution since before XHCI finish the whole > initialization, USB2 root hub triggered runtime suspend is mean less and do > not need to handle. With this patch applied, does the crash go away? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
