Hi Grigor,
On Wed, May 02, 2018 at 10:12:27AM +0000, Grigor Tovmasyan wrote:
> Hi Simon,
>
> On 4/21/2018 4:52 PM, Simon Shields wrote:
> > Hi Grigor,
> >
> > On Fri, Apr 20, 2018 at 01:00:16PM +0000, Grigor Tovmasyan wrote:
> >> Hi Simon,
> >>
> >> On 4/19/2018 8:31 PM, Simon Shields wrote:
> >>> Hi all,
> >>>
> >>> On 10/04/2018 10:21 PM, Grigor Tovmasyan wrote:
> >>>> Here are two little fixes for LPM feature.
> >>>>
> >>>> First one is coverity warning fix.
> >>>>
> >>>> The Second one was asserted by Stefan Wahren.
> >>>>
> >>>> Changes from version 0:
> >>>>
> >>>> 1/2:
> >>>> - Instead of converting parameter in the CHECK_RANGE macro
> >>>> to int, changed hird_threshold type from u8 to int.
> >>>>
> >>>>
> >>>> Grigor Tovmasyan (2):
> >>>> usb: dwc2: gadget: Fix coverity issue
> >>>> usb: dwc2: gadget: Change LPM default values
> >>>>
> >>>> drivers/usb/dwc2/core.h | 2 +-
> >>>> drivers/usb/dwc2/params.c | 8 ++++----
> >>>> 2 files changed, 5 insertions(+), 5 deletions(-)
> >>>
> >>> The second patch in this series fixes a regression in 4.17-rc1 using dwc2 in gadget
> >>> mode on Exynos4412, introduced by commit 7455f8b7f0b3 ("usb: dwc2: Enable
> >>> LPM"). The regression is that using the cdc_acm serial gadget (and
> >>> presumably other gadgets) serial console output will only sporadically
> >>> show up on the host (it seems to only show up as input is sent).
> >>>
> >> The second patch is not fix for described by you issue. We will try to
> >> reproduce your issue and provide fix. Could you provide some logs or usb
> >> traces for issue?
> >
> > Here's a log[0]. The log is pretty big: I generated it with both regular and verbose
> > debugging enabled for DWC2. However, I suspect the relevant line is
> > probably:
> >
> > [ 95.222330] dwc2 12480000.hsotg: dwc2_hsotg_ep_queue: submit request only in active state
> >
> > Which occurs whenever the controller is in LPM mode. I guess that input
> > makes it "work" because it reawakens the controller -- but I'm just
> > spitballing :-). Let me know if you need any more information from my
> > side.
> >
> > [0]: https://urldefense.proofpoint.com/v2/url?u=https-3A__forkwhiletrue.me_-7Esimon_midas-5Fdwc2-5Flpm-5Fverbose.log&d=DwIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=K1ULVL1slpLXpMJJlAXSOxws4tRq0IkTBqxDkyW2hUQ&m=fkdnWR9_dgHLGH5-mN9lDclJ58GWR__m7hS3zz3am28&s=aind-wCFaB40EyTcHvphrqt6SngQTnf3CYXJxOfBjWc&e=
> >
> >>
> >>> However, I'm unsure if completely disabling LPM is the correct fix, as the dwc2
> >>> revision in Exynos4412 (0x4f54281a) should support LPM according to the
> >>> source
> >> Yes, we can enable LPM based on hardware configuration.
> >>
> >>> I'm not really sure how to debug this any further (vendor kernel
> >>> releases contain no mention of LPM in the gadget drivers), so any pointers
> >>> in that direction would be much appreciated.
> >>>
> >>> Cheers,
> >>> Simon
> >>>
> >>
> >
> > Cheers,
> > Simon
> >
>
> Could you please revert "usb: dwc2: Add core state checking" patch and
> try again.
This doesn't really fix the issue, but it does change the results. Now, input works
as expected, but output is still only shown after input is given (e.g.
the output of "dmesg" only shows if I press a key after executing dmesg).
However, after a few seconds the USB serial device disappears from the
host entirely. Once this has happened, reading the "regdump" of dwc2's debugfs
appears to hang the system (i.e. it no longer responds to UART). I've attached
another log[0].
[0]: https://forkwhiletrue.me/~simon/midas_dwc2_revert_verbose.log
>
> Let me know about result.
>
> Thanks,
> Grigor.
Cheers,
Simon
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