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.

thanks,

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to