From: Ross Zwisler <firstname.lastname@example.org> To: Mathias Nyman <email@example.com> Cc: Andrzej Pietrasiewicz <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org> Subject: Re: xhci problem -> general protection fault Date: Tue, 8 Dec 2020 10:24:40 -0700 Message-ID: <X8+22DeNDn1A7X+N@google.com> (raw) In-Reply-To: <email@example.com> On Fri, Dec 04, 2020 at 08:07:30PM +0200, Mathias Nyman wrote: <> > Ok, thanks. > > Then the rootcause remains unknown. > For some reason the endpoint context dequeue pointer field contains zero > instead of the new dequeue pointer. > The (output) endpoint context is supposed to be written only by the controller. > > Time to change strategy and start to detect and treat the symptoms instead. > > I wrote a patch that detects the 0-dequeue pointer and issues a > new Set TR Deq pointer command. Hopefully that works. > patch added to same branch, can you try it out? > > 3f6326766abc xhci: retry setting new dequeue if xHC hardware failed to update it > > I didn't set a retry limit yet so if it doesn't work it might retry forever. Here are some logs when running with that commit: https://gist.github.com/rzwisler/17923c9dedf2b914254eadd1cd294a4c I think we only consistently get the clean failure case with the dequeue pointer being 0 if CONFIG_INTEL_IOMMU_DEFAULT_ON=y. If that option is set to 'n', we get the same failure where the xHCI controller totally dies (log "CONFIG_INTEL_IOMMU_DEFAULT_ON=n" in the gist). With CONFIG_INTEL_IOMMU_DEFAULT_ON=y we do seem to live through multiple errors, but as soon as I try to use the device normally afterwards it seems to spin forever with these messages: xhci_hcd 0000:00:14.0: Looking for event-dma 00000000fff0a330 trb-start 00000000f8884000 trb-end 0000000000000000 seg-start 00000000f8884000 seg-end 00000000f8884ff0 Are you able to reproduce this with Andrzej's bulk-cancel script? I think you probably just need a device which accepts bulk transfer commands? In my most recent reproductions my servo hardware wasn't even attached to a device, so I don't really think it's doing anything except sitting there and receiving BULK_IN commands. I'm doing this to two devices simultaneously.
next prev parent reply index Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-17 15:30 Andrzej Pietrasiewicz 2020-09-18 10:50 ` Mathias Nyman 2020-09-18 14:20 ` Andrzej Pietrasiewicz 2020-09-25 13:40 ` Mathias Nyman 2020-09-25 21:05 ` Ross Zwisler 2020-09-28 13:32 ` Andrzej Pietrasiewicz 2020-09-29 7:13 ` Mathias Nyman 2020-10-01 14:13 ` Andrzej Pietrasiewicz 2020-09-28 22:35 ` Mathias Nyman 2020-10-01 16:43 ` zwisler 2020-10-12 19:20 ` Mathias Nyman 2020-10-12 21:53 ` zwisler 2020-10-13 7:49 ` Mathias Nyman 2020-10-13 8:29 ` Andrzej Pietrasiewicz 2020-10-13 16:44 ` zwisler 2020-11-19 16:52 ` Ross Zwisler 2020-11-23 15:06 ` Mathias Nyman 2020-12-02 22:59 ` Ross Zwisler 2020-12-04 18:07 ` Mathias Nyman 2020-12-08 17:24 ` Ross Zwisler [this message] 2020-12-09 13:11 ` Mathias Nyman 2020-12-09 18:54 ` Ross Zwisler 2020-12-30 12:33 ` Mathias Nyman 2021-01-06 18:52 ` Ross Zwisler 2021-01-07 8:57 ` Mathias Nyman 2021-01-07 16:07 ` Ross Zwisler
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