On Fri, Jan 8, 2021 at 4:26 AM Felipe Balbi <balbi@xxxxxxxxxx> wrote: > > > Hi, > > John Stultz <john.stultz@xxxxxxxxxx> writes: > > From: Yu Chen <chenyu56@xxxxxxxxxx> > > > > Just resending this, as discussion died out a bit and I'm not > > sure how to make further progress. See here for debug data that > > was requested last time around: > > https://lore.kernel.org/lkml/CALAqxLXdnaUfJKx0aN9xWwtfWVjMWigPpy2aqsNj56yvnbU80g@xxxxxxxxxxxxxx/ > > > > With the current dwc3 code on the HiKey960 we often see the > > COREIDLE flag get stuck off in __dwc3_gadget_start(), which > > seems to prevent the reset irq and causes the USB gadget to > > fail to initialize. > > > > We had seen occasional initialization failures with older > > kernels but with recent 5.x era kernels it seemed to be becoming > > much more common, so I dug back through some older trees and > > realized I dropped this quirk from Yu Chen during upstreaming > > as I couldn't provide a proper rational for it and it didn't > > seem to be necessary. I now realize I was wrong. > > > > After resubmitting the quirk, Thinh Nguyen pointed out that it > > shouldn't be a quirk at all and it is actually mentioned in the > > programming guide that it should be done when switching modes > > in DRD. > > > > So, to avoid these !COREIDLE lockups seen on HiKey960, this > > patch issues GCTL soft reset when switching modes if the > > controller is in DRD mode. > > > > Cc: Felipe Balbi <balbi@xxxxxxxxxx> > > Cc: Tejas Joglekar <tejas.joglekar@xxxxxxxxxxxx> > > Cc: Yang Fei <fei.yang@xxxxxxxxx> > > Cc: YongQin Liu <yongqin.liu@xxxxxxxxxx> > > Cc: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx> > > Cc: Thinh Nguyen <thinhn@xxxxxxxxxxxx> > > Cc: Jun Li <lijun.kernel@xxxxxxxxx> > > Cc: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> > > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > Cc: linux-usb@xxxxxxxxxxxxxxx > > Signed-off-by: Yu Chen <chenyu56@xxxxxxxxxx> > > Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> > > --- > > v2: > > * Rework to always call the GCTL soft reset in DRD mode, > > rather then using a quirk as suggested by Thinh Nguyen > > > > v3: > > * Move GCTL soft reset under the spinlock as suggested by > > Thinh Nguyen > > Because this is such an invasive change, I would prefer that we get > Tested-By tags from a good fraction of the users before applying these > two changes. I'm happy to reach out to folks to try to get that. Though I'm wondering if it would be better to put it behind a dts quirk flag, as originally proposed? https://lore.kernel.org/lkml/20201021181803.79650-1-john.stultz@xxxxxxxxxx/ That way folks can enable it for devices as they need? Again, I'm not trying to force this in as-is, just mostly sending it out again for discussion to understand what other approach might work. thanks -john
