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Date:   Fri, 18 Mar 2022 08:45:19 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     "WeitaoWang-oc@zhaoxin.com" <WeitaoWang-oc@zhaoxin.com>
Cc:     mathias.nyman@intel.com, hzpeterchen@gmail.com,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        TonyWWang-oc@zhaoxin.com, weitaowang@zhaoxin.com,
        CobeChen@zhaoxin.com, TimGuo@zhaoxin.com
Subject: Re: [PATCH] USB: Fix xhci ERDP update issue
Message-ID: <YjQ4jzgRmrDJClUZ@kroah.com>
References: <dedb789b-c1bb-34af-7887-78a3fc627e75@zhaoxin.com>
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In-Reply-To: <dedb789b-c1bb-34af-7887-78a3fc627e75@zhaoxin.com>
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On Fri, Mar 18, 2022 at 03:32:14PM +0800, WeitaoWang-oc@zhaoxin.com wrote:
> On some situations, software handles TRB events slower than adding TRBs.
> If the number of TRB events to be processed in a given interrupt is 256.
> The local variable "event_ring_deq" that records in interrupt handler
> is equal to software_dequeue. It will cause driver not update ERDP,then
> software dequeue pointer is out of sync with ERDP on interrupt exit.
> On the next interrupt, the event ring may full but driver will not
> update ERDP as software_dequeue is equal to ERDP.
> 
> [  536.377115] xhci_hcd 0000:00:12.0: ERROR unknown event type 37
> [  566.933173] sd 8:0:0:0: [sdb] tag#27 uas_eh_abort_handler 0 uas-tag 7
> inflight: CMD OUT
> [  566.933181] sd 8:0:0:0: [sdb] tag#27 CDB: Write(10) 2a 00 17 71 e6 78 00
> 00 08 00
> [  572.041186] xhci_hcd On some situataions,the0000:00:12.0: xHCI host not
> responding to stop endpoint command.
> [  572.057193] xhci_hcd 0000:00:12.0: Host halt failed, -110
> [  572.057196] xhci_hcd 0000:00:12.0: xHCI host controller not responding,
> assume dead
> [  572.057236] sd 8:0:0:0: [sdb] tag#26 uas_eh_abort_handler 0 uas-tag 6
> inflight: CMD
> [  572.057240] sd 8:0:0:0: [sdb] tag#26 CDB: Write(10) 2a 00 38 eb cc d8 00
> 00 08 00
> [  572.057244] sd 8:0:0:0: [sdb] tag#25 uas_eh_abort_handler 0 uas-tag 5
> inflight: CMD
> 
> Fixed this issue by update software record local variable when handles 128
> TRB events.
> 
> Signed-off-by: Weitao Wang <WeitaoWang-oc@zhaoxin.com>
> ---
>  drivers/usb/host/xhci-ring.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index d0b6806..f970799 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -3141,6 +3141,7 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
>  		if (event_loop++ < TRBS_PER_SEGMENT / 2)
>  			continue;
>  		xhci_update_erst_dequeue(xhci, event_ring_deq);
> +		event_ring_deq = xhci->event_ring->dequeue;
> 
>  		/* ring is half-full, force isoc trbs to interrupt more often */
>  		if (xhci->isoc_bei_interval > AVOID_BEI_INTERVAL_MIN)
> -- 
> 2.7.4

What commit id does this change fix?

thanks,

greg k-h