Hi Felipe, On Thursday, August 15, 2019 13:59, Felipe Balbi wrote: > > Hi, > > Yinbo Zhu <yinbo....@nxp.com> writes: > >> Yinbo Zhu <yinbo....@nxp.com> writes: > >> >> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > >> >> > index > >> >> > 98bce85c29d0..a133d8490322 100644 > >> >> > --- a/drivers/usb/dwc3/core.c > >> >> > +++ b/drivers/usb/dwc3/core.c > >> >> > @@ -300,8 +300,7 @@ static void > >> >> > dwc3_frame_length_adjustment(struct > >> >> > dwc3 *dwc) > >> >> > > >> >> > reg = dwc3_readl(dwc->regs, DWC3_GFLADJ); > >> >> > dft = reg & DWC3_GFLADJ_30MHZ_MASK; > >> >> > - if (!dev_WARN_ONCE(dwc->dev, dft == dwc->fladj, > >> >> > - "request value same as default, ignoring\n")) { > >> >> > + if (dft != dwc->fladj) { > >> >> > >> >> if the value isn't different, why do you want to change it? > >> >> > >> >> -- > >> >> Balbi > >> > Hi Balbi, > >> > > >> > I don't change any value. I was remove that call trace. > >> > >> Sure you do. The splat only shows when you request a FLADJ value > >> that's the same as the one already in the register. The reason you > >> see the splat is because your requested value is what's already in the HW. > >> > >> So, again, why are you adding this device tree property if the value > >> is already the correct one? > >> > >> > In addition that GFLADJ_30MHZ value intial value is 0, and it's > >> > value must be 0x20, if not, usb will not work. > >> > >> it's not zero, otherwise the splat wouldn't trigger. You're > >> requesting the value that's already in your register by default. > >> > >> -- > >> Balbi > > > > Hi Balbi, > > > > According that rm doc that GFLADJ_30MHZ has a default value is 0x20, > > when GFLADJ_30MHZ_REG_SEL is 0, this 0x20 is a hard-coded value. > > > > But in fact, that default value is 0, please you note! > > > > Then according that xhci spec 5.2.4, that register the sixth bit if is > > 0, then that can support Frame Lenth Timing value. > > > > So set GFLADJ_30MHZ_REG_SEL to 1 for use FLADJ, then I find that it > > must use 0x20 usb will work well, even thoug xhci can permit > > GFLADJ_30MHZ use other value > > You only get the splat because you try to sent GFLADJ to 0x20 and it's ALREADY > 0x20. This means that you don't need the property in DTS. > > > In addition about what you said is about dts patch, and that patch had > > merged by upstream, patch owner isn't me, > > Well, then remove the setting from DTS, since clearly it's not needed.
Please considering below scenarios on the same board which needs GFLADJ property on kernel DTS: 1. Board boot to U-Boot first, then load kernel. In this case, we need kernel DTS help to get GFLADJ setting right, everything is as expected. 2. Board boot to U-Boot console, then execute 'usb start' under U-Boot console to init DWC3 controller, then load kernel. In this case, actually GFLADJ is correctly configured already, and the GFLADJ config double-checking is fine (because kernel cannot know if U-Boot has initialized it or not), but warning looks not necessary. 3. Board boot to kernel, GFLADJ get set from DTS, then system suspend & resume. In this case when resuming, GFLADJ setting has been restored correctly, so here we might not need send out the warning message (double-checking might be fine). So, what's your suggestion to remove this looks non-necessary warning message? Thanks & Regards, Ran > > My patch is only for remove the call-trace, about why remove it commit > > information has detail introduce please check! > > -- > balbi