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.

Gives more time to look at the usb core changes. I'm not really
myself running or testing the dwc3 host side.

-Mathias
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