Hi Rob, > -----Original Message----- > From: Rob Herring <robh@xxxxxxxxxx> > Sent: Wednesday, February 27, 2019 00:40 > To: Ran Wang <ran.wang_1@xxxxxxx> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; Yang Li > <pku.leo@xxxxxxxxx>; linux-usb@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; Ran Wang <ran.wang_1@xxxxxxx> > Subject: Re: [PATCH v3 1/2] usb: dwc3: Add avoiding vbus glitch happen during > xhci reset > > On Tue, 26 Feb 2019 06:59:21 +0000, Ran Wang wrote: > > When DWC3 is set to host mode by programming register DWC3_GCTL, VBUS > > (or its control signal) will turn on immediately on related Root Hub > > ports. Then the VBUS will be de-asserted for a little while during > > xhci reset (conducted by xhci driver) for a little while and back to normal. > > > > This VBUS glitch might cause some USB devices emuration fail if kernel > > boot with them connected. One SW workaround which can fix this is to > > program all PORTSC[PP] to 0 to turn off VBUS immediately after setting > > host mode in DWC3 driver(per signal measurement result, it will be too > > late to do it in xhci-plat.c or xhci.c). > > > > Signed-off-by: Ran Wang <ran.wang_1@xxxxxxx> > > --- > > Changes in v3: > > - None > > > > Changes in v2: > > - Correct typos > > - Shorten the name to snps,host-vbus-glitches > > > > Documentation/devicetree/bindings/usb/dwc3.txt | 3 +++ > > 1 files changed, 3 insertions(+), 0 deletions(-) > > > > Please add Acked-by/Reviewed-by tags when posting new versions. However, > there's no need to repost patches *only* to add the tags. The upstream > maintainer will do that for acks received on the version they apply. Got it, thanks for telling me this. So if I need to update patch 2/2 in next version, I still need to attach this 1/2 patch with adding tag 'Reviewed-by' to it, am I right? > > If a tag was not added on purpose, please state why and what changed. OK Regards, Ran
