On 05/23/2013 05:11 PM, Alan Stern wrote: > On Thu, 23 May 2013, Roger Quadros wrote: > >> Device tree probed devices don't get dma_mask set. Previously >> we were setting the dma_mask pointer only if it was NULL. >> However, the address of 'omap_ehci_dma_mask' would change >> each time the module is unloaded and loaded back thus causing >> the devices dma_mask pointer to be invalid on the next load. >> >> This will cause page faults if any driver tries to access the >> old dma_mask pointer. >> >> Unconditionally re-setting the dma_mask pointer fixes this problem. > >> diff --git a/drivers/usb/host/ehci-omap.c b/drivers/usb/host/ehci-omap.c >> index 3d1491b..b33e306 100644 >> --- a/drivers/usb/host/ehci-omap.c >> +++ b/drivers/usb/host/ehci-omap.c >> @@ -146,8 +146,7 @@ static int ehci_hcd_omap_probe(struct platform_device *pdev) >> * Since shared usb code relies on it, set it here for now. >> * Once we have dma capability bindings this can go away. >> */ >> - if (!pdev->dev.dma_mask) >> - pdev->dev.dma_mask = &omap_ehci_dma_mask; >> + pdev->dev.dma_mask = &omap_ehci_dma_mask; > > Is this the solution that people have agreed on? There has been a lot > of discussion on this topic. In particular, there has been talk about > fixing it in the DT core. Fixing it in DT core would be best. > > This particular approach doesn't seem very robust. What if > pdev->dev.dma_mask is already set to a different value for some good > reason? > Then it breaks. But for OMAP, that situation seems unlikely. cheers, -roger -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
