> This e-mail is a follow-up as requested in this bug[1]. I will repost
> everything so far in this e-mail. Please CC me as I'm not subscribed
> to your list.
>
> Current head gives this when I plug a 'Mass Storage Device' into a 2.0 hub:
>
> [ 842.760400] hub 1-0:1.0: unable to enumerate USB device on port 3
> [ 843.080058] usb 1-3: new high-speed USB device number 48 using ehci-pci
> [ 858.230072] usb 1-3: device descriptor read/64, error -110
> [ 873.490070] usb 1-3: device descriptor read/64, error -110
>
> Reverting the following commit makes it work again:
>
> commit 55bcdce8a8228223ec4d17d8ded8134ed265d2c5
> Author: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> Date: Fri Jan 25 16:52:45 2013 -0500
>
> USB: EHCI: remove ASS/PSS polling timeout
>
> This patch (as1647) attempts to work around a problem that seems to
> affect some nVidia EHCI controllers. They sometimes take a very long
> time to turn off their async or periodic schedules. I don't know if
> this is a result of other problems, but in any case it seems wise not
> to depend on schedule enables or disables taking effect in any
> specific length of time.
>
> The patch removes the existing 20-ms timeout for enabling and
> disabling the schedules. The driver will now continue to poll the
> schedule state at 1-ms intervals until the controller finally decides
> to obey the most recent command issued by the driver. Just in case
> this hides a problem, a debugging message will be logged if the
> controller takes longer than 20 polls.
>
> I don't know if this will actually fix anything, but it can't hurt.
>
> Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> Tested-by: Piergiorgio Sartor <piergiorgio.sartor@xxxxxxxx>
> CC: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>
> diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c
> index 20dbdcb..f904071 100644
> --- a/drivers/usb/host/ehci-timer.c
> +++ b/drivers/usb/host/ehci-timer.c
> @@ -113,14 +113,15 @@ static void ehci_poll_ASS(struct ehci_hcd *ehci)
>
> if (want != actual) {
>
> - /* Poll again later, but give up after about 20 ms */
> - if (ehci->ASS_poll_count++ < 20) {
> - ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true);
> - return;
> - }
> - ehci_dbg(ehci, "Waited too long for the async schedule
> status(%x/%x), giving up\n",
> - want, actual);
> + /* Poll again later */
> + ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true);
> + ++ehci->ASS_poll_count;
> + return;
> }
> +
> + if (ehci->PSS_poll_count > 20)
> + ehci_dbg(ehci, "PSS poll count reached %d\n",
> + ehci->PSS_poll_count);
> ehci->PSS_poll_count = 0;
>
> /* The status is up-to-date; restart or stop the schedule as needed */
>
> Please note, that I'm using the 'irqpoll' cmdline to improve system
> stability. What I forgot to mention in the bug was the chipset:
>
> 00:10.3 USB controller: VIA Technologies, Inc. USB 2.0 (rev 82)
> (prog-if 20 [EHCI])
> Subsystem: Micro-Star International Co., Ltd. KT4AV motherboard
> Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr-
> Stepping- SERR- FastB2B- DisINTx-
> Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
> <TAbort- <MAbort- >SERR- <PERR- INTx-
> Latency: 32, Cache Line Size: 32 bytes
> Interrupt: pin D routed to IRQ 21
> Region 0: Memory at dffeff00 (32-bit, non-prefetchable) [size=256]
> Capabilities: [80] Power Management version 2
> Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
> Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
> Kernel driver in use: ehci-pci
>
> Yes, it's 10 years old, and no I'm not scrooge. We are waiting a while
> for computer prices to plummet mkay?
>
> [1]: https://bugzilla.kernel.org/show_bug.cgi?id=54031
Would like to add that while searching the mailing lists I stumbled on this:
http://marc.info/?l=linux-usb&m=136045531311402&w=4
It's an entirely seperate USB issue in this cycle. The person is doing
git bisect to find the regression. I did another approach as
recompiling the full kernel on a 1,25GHz isn't even remotely funny
anymore.
On top of HEAD I started reverting groups of USB EHCI patches one by
one. I'm just mentioning it since I'm not sure if this procedure is
accepted here.
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