On Fri, Jun 07, 2013 at 11:37:53PM +0300, Felipe Balbi wrote: > Hi, > > On Fri, Jun 07, 2013 at 10:19:23AM -0700, Sarah Sharp wrote: > > Adding Felipe. > > > > Xenia, Felipe is the USB "gadget" maintainer, and also added code for > > non-PCI xHCI hosts. Felipe, Xenia is my summer intern through the FOSS > > Outreach Program for Women: http://kernelnewbies.org/OPWIntro > > Hey, cool Sarah :-) > > Welcome Xenia :-) Ah, slight correction, my intern wants to be called Ksenia. Xenia is her legal name, but everyone calls her Ksenia. :) > > On Fri, Jun 07, 2013 at 03:00:47PM +0300, Mathias Nyman wrote: > > > Andy explained his concern in more detail to me irl. > > > > > > The beef is that the dma_mask is a pointer while dma_coherent_mask > > > is a u64 value in struct device, and dma_set_mask() fails if > > > dev->dma_mask doesn't point anywhere. > > > > > > This is not a problem for PCI enumerated devices because PCI probe > > > sets a default 32bit mask and makes the dma_mask of all new PCI > > > devices point to this value. > > > > > > For non-pci enumerated devices the device dma_mask may be NULL and > > > dma_set_mask() may fail even if dma is supported on the host > > > machine. > > > > > > for example ehci-platform.c solves this by adding: > > > > > > if (!dev->dev.dma_mask) > > > dev->dev.dma_mask = &dev->dev.coherent_dma_mask; > > > if (!dev->dev.coherent_dma_mask) > > > dev->dev.coherent_dma_mask = DMA_BIT_MASK(32); > > > > So it sounds like xhci_plat_setup() in xhci-plat.c needs to do something > > similar before it calls xhci_gen_setup(). Felipe, do you agree? > > (now, after reading the whole thing...) > > I'll agree with that :) > > > It's funny that the code worked before. Perhaps setting the dma_mask > > pointer should be a separate patch for stable? > > sounds like a good plan to me :-) Great! Ok, Ksenia, can you create those two patches? The first patch in the series should add setting the dma_mask pointer to xhci_plat_setup(). The second patch will be the same as this patch. Let me know via IRC if you have any questions. Sarah Sharp -- 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
