On 20.02.20 16:37, Jun Li wrote: > > >> -----Original Message----- >> From: Martin Kepplinger <martin.kepplinger@xxxxxxx> >> Sent: 2020年2月20日 19:44 >> To: Jun Li <jun.li@xxxxxxx>; Peter Chen <peter.chen@xxxxxxx>; >> mathias.nyman@xxxxxxxxx >> Cc: linux-usb@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; Anson Huang >> <anson.huang@xxxxxxx>; shawnguo@xxxxxxxxxx; kernel@xxxxxxxxxxxxxx >> Subject: Re: [PATCH] usb: host: xhci-plat: add XHCI_MISSING_CAS quirk >> >> On 20.02.20 07:31, Jun Li wrote: >>>> -----Original Message----- >>>> From: Martin Kepplinger <martin.kepplinger@xxxxxxx> >>>> Sent: 2020年2月20日 1:37 >>>> To: Jun Li <jun.li@xxxxxxx>; Peter Chen <peter.chen@xxxxxxx>; >>>> mathias.nyman@xxxxxxxxx >>>> Cc: linux-usb@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; >>>> Anson Huang <anson.huang@xxxxxxx>; shawnguo@xxxxxxxxxx; >>>> kernel@xxxxxxxxxxxxxx >>>> Subject: [PATCH] usb: host: xhci-plat: add XHCI_MISSING_CAS quirk >>>> >>>> From: Li Jun <jun.li@xxxxxxx> >>>> >>>> i.MX8MQ USB3 host needs XHCI_MISSING_CAS quirk to warm reset the port >>>> to enum the >>>> USB3 device plugged in while system sleep, as the port state is stuck >>>> in polling mode after resume. >>>> >>>> Signed-off-by: Li Jun <jun.li@xxxxxxx> >>>> Acked-by: Peter Chen <peter.chen@xxxxxxx> >>>> --- >>>> >>>> Hi, >>>> >>>> Because resume from S3 suspend is broken for me on imx8mq, I stumbled >>>> upon this patch in NXP's linux tree. (Please note that I'm not the >>>> author and I've not yet put my SoB tag under it). This is just a >>>> question: >>>> >>>> This patch (and the docs) clearly is missing in mainline Linux >>>> because the imx8mq devicetree description includes it (which does nothing now). >>>> >>>> I've tested this and this particular addition doesn't fix my problem: >>>> >>>> [ 84.257538] imx8mq-usb-phy 381f0040.usb-phy: bus resume >>>> [ 84.263195] imx8mq-usb-phy 382f0040.usb-phy: bus resume >>>> [ 84.268898] dwc3 38100000.usb: driver resume >>>> >>>> during resume from S3 suspend, here it still hangs. >>> >>> Is your problem a system hang? If yes, this may another issue, where >>> the hang happens? dwc3_resume_common()? >> >> exactly! I followed to the point it hangs once again and it's >> >> dwc3_core_init() called from dwc3_resume_common()'s "OTG" case. >> >> Specifically, dwc3_writel() is what I don't get past: >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir.bootl >> in.com%2Flinux%2Fv5.6-rc2%2Fsource%2Fdrivers%2Fusb%2Fdwc3%2Fcore.c%23L934& >> data=02%7C01%7Cjun.li%40nxp.com%7C130cd29875c44792d1a908d7b5fa2516%7C686ea1d3b >> c2b4c6fa92cd99c5c301635%7C0%7C0%7C637177958284696041&sdata=mqh9MH6ESLVxKvW >> vvMq4vwt2dcTuvNopgGVdXEbbMwk%3D&reserved=0 > > So while dwc3 resume, the first register access cause hang. > Looks like some required clocks or power domain of USB0 is not on. which would these be in imx8mq.dtsi ? > >> >> do you have an idea why this writel() hangs? > > I never encounter such hang on my iMX8MQ EVK board > using upstream kernel(5.x) + changes of enable USB0 port, > but I didn't try latest 5.6 kernel. > I will enable the first port based on Linux-next to give a > try on my NXP iMX8MQ EVK board, do you think I can reproduce > your problem? > > Li Jun Hi Li, thanks for taking a look. I would think that you can reproduce that, yes. I'm running v5.6-rc2 with no changes to usb or any relevant changes to clk (I think), but in case you're curious, this is the whole tree: https://source.puri.sm/Librem5/linux-next/tree/imx8-linux-next-librem5 What "changes of enable USB0 port" do you mean? thanks, martin >> >>> >>> The question patch is to give a warm reset for connected USB device if >>> the link state is not connect/CAS after system resume, otherwise host >>> will wait 2s for device appear: >>> >>> [ 44.834831] usb 2-1: Waited 2000ms for CONNECT >>> ... >>> [ 45.055718] PM: resume devices took 3.132 seconds >>> >>> I will post this patch and doc(to be updated) to upstream later. >>> >> >> ok, good, thanks, >> >> martin >
