On 30/03/16 21:44, John Youn wrote: > On 3/23/2016 11:52 PM, Felipe Balbi wrote: >> >> Hi, >> >> John Youn <John.Youn@xxxxxxxxxxxx> writes: >>> [ text/plain ] >>> On 3/21/2016 11:40 PM, Felipe Balbi wrote: >>>> >>>> Hi, >>>> >>>> John Youn <John.Youn@xxxxxxxxxxxx> writes: >>>>> [ text/plain ] >>>>> On 3/18/2016 12:17 PM, John Youn wrote: >>>>>> On 3/16/2016 6:56 AM, Felipe Balbi wrote: >>>>>>> >>>>>>> heh, +john >>>>>>> >>>>>>> Felipe Balbi <balbi@xxxxxxxxxx> writes: >>>>>>>> [ text/plain ] >>>>>>>> >>>>>>>> Hi, >>>>>>>> >>>>>>>> Roger Quadros <rogerq@xxxxxx> writes: >>>>>>>>> [ text/plain ] >>>>>>>>> We will need this function for a workaround. >>>>>>>>> The function issues a softreset only to the device >>>>>>>>> controller and performs minimal re-initialization >>>>>>>>> so that the device controller can be usable. >>>>>>>>> >>>>>>>>> As some code is similar to dwc3_core_init() take out >>>>>>>>> common code into dwc3_get_gctl_quirks(). >>>>>>>>> >>>>>>>>> We add a new member (prtcap_mode) to struct dwc3 to >>>>>>>>> keep track of the current mode in the PRTCAPDIR register. >>>>>>>>> >>>>>>>>> Signed-off-by: Roger Quadros <rogerq@xxxxxx> >>>>>>>> >>>>>>>> I must say, I don't like this at all :-p There's ONE known silicon which >>>>>>>> needs this because of a poor silicon integration which took an IP with a >>>>>>>> known erratum where it can't be made to work on lower speeds and STILL >>>>>>>> was integrated without a superspeed PHY. >>>>>>>> >>>>>>>> There's a reason why I never tried to push this upstream myself ;-) >>>>>>>> >>>>>>>> I'm really thinking we might be better off adding a quirk flag to skip >>>>>>>> the metastability workaround and allow this ONE silicon to set the >>>>>>>> controller to lower speed. >>>>>>>> >>>>>>>> John, can you check with your colleagues if we would ever fall into >>>>>>>> STAR#9000525659 if we set maximum speed to high speed during driver >>>>>>>> probe and never touch it again ? I would assume we don't really fall >>>>>>>> into the metastability workaround, right ? We're not doing any sort of >>>>>>>> PM for dwc3... >>>>>>>> >>>>> >>>>> Hi Felipe, >>>>> >>>>> Do you mean to keep DCFG.speed to SS and set dwc->maximum_speed to HS? >>>>> I don't see an issue with that as long as we always ignore >>>>> dwc->maximum_speed when programming DCFG.speed for all affected >>>>> versions of the core. As long as the DCFG.speed = SS, you should not >>>>> hit the STAR. >>>> >>>> I actually mean changing DCFG.speed during driver probe and never >>>> touching it again. Would that still cause problems ? >>>> >>> >>> In that case I'm not sure. The engineer who would know is off until >>> next week so I'll get back to you as soon as I can talk to him about >>> it. >> > > So the engineers said that this issue can occur while set to HS and > the run/stop bit is changed so it seems that won't work. Thanks John. Felipe, any suggestion how we can fix this upstream? cheers, -roger -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
