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://forkwhiletrue.me/~simon/midas_dwc2_lpm_verbose.log
>
> > 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
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