On Fri, Jan 20, 2017 at 02:08:50PM +0200, Felipe Balbi wrote:
> 
> Hi,
> 
> Greg KH <gre...@linuxfoundation.org> writes:
> > On Fri, Jan 20, 2017 at 01:35:39PM +0200, Mathias Nyman wrote:
> >> On 20.01.2017 12:22, Greg KH wrote:
> >> > On Fri, Jan 20, 2017 at 11:23:36AM +0200, Mathias Nyman wrote:
> >> > > On 19.01.2017 20:48, Greg KH wrote:
> >> > > > On Thu, Jan 19, 2017 at 02:21:26PM +0200, Mathias Nyman wrote:
> >> > > > > Hi Greg
> >> > > > > 
> >> > > > > This series by Arnd Bergmann was originally six patches, but last 
> >> > > > > two of
> >> > > > > them were already taken to 4.10. Without the rest of them there 
> >> > > > > will
> >> > > > > be a regression in 4.10.
> >> > > > 
> >> > > > Is it really a regression?  I thought this had never worked before in
> >> > > > older kernels, right?
> >> > > > 
> >> > > 
> >> > > Regression when xhci hosts in dwc3 controllers are used.
> >> > 
> >> > So that worked in 4.9?
> >> > 
> >> > > For example patch 5/6 removed setting dma mask for xhci in dwc3 host 
> >> > > init:
> >> > > 
> >> > > +++ b/drivers/usb/dwc3/host.c
> >> > > @@ -84,11 +84,7 @@ int dwc3_host_init(struct dwc3 *dwc)
> >> > >                return -ENOMEM;
> >> > >        }
> >> > > -      dma_set_coherent_mask(&xhci->dev, dwc->dev->coherent_dma_mask);
> >> > > -
> >> > >        xhci->dev.parent        = dwc->dev;
> >> > > -      xhci->dev.dma_mask      = dwc->dev->dma_mask;
> >> > > -      xhci->dev.dma_parms     = dwc->dev->dma_parms;
> >> > > 
> >> > > So now xhci platform driver prints a scary warning because of the 
> >> > > missing dma mask:
> >> > > 
> >> > > static int xhci_plat_probe(struct platform_device *pdev)
> >> > >   /* Try to set 64-bit DMA first */
> >> > >        if (WARN_ON(!pdev->dev.dma_mask))
> >> > >                  /* Platform did not initialize dma_mask */
> >> > >                  ret = dma_coerce_mask_and_coherent(&pdev->dev,
> >> > >                                                     DMA_BIT_MASK(64));
> >> > >          else
> >> > >        ...
> >> > > This is fixed in the first 4 patches.
> >> > > 
> >> > > There might be other other issues as well caused by having only the 
> >> > > dwc3
> >> > > changed applied of this series, but not the core and xhci parts
> >> > 
> >> > Should we just fix the "scary warning" instead, by removing it?  :)
> >> > 
> >> > I say all of this because this seems like some very big changes so late
> >> > in the -rc cycle.
> >> > 
> >> 
> >> I guess that would work, or at least get us to the same stage as 4.9.
> >> I'll send a patch for it.
> >
> > Great.
> >
> >> Gives more time to look at the usb core changes. I'm not really
> >> myself running or testing the dwc3 host side.
> >
> > Me either.  Any hints on some hardware that would allow me to do that?
> 
> Intel Edison.

Ah nice, if only I knew someone at Intel who could get me one of
those... :)

> Or any recent TI board (AM437x SK, for instance).

Will that run a mainline kernel?

> Google Pixel Phone (but good luck running a mainline kernel there ;-)

I have a Pixel phone here, but haven't been paying attention to the dwc3
interface.  Is dwc3 a block in the SoC on the Pixel?  I have another
device here with the same SoC as the Pixel (OnePlus 3T) that I can run
my own kernel on, but it's a bit older version, due to SoC issues (same
one the Pixel has at the moment...)  However some of us have a crazy
idea to drag that platform up to mainline over the next few months.

thanks,

greg k-h
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