From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Quadros Subject: Re: [PATCH 1/1] USB: ehci-omap: Reset dma_mask pointer on probe Date: Tue, 4 Jun 2013 12:48:05 +0300 Message-ID: <51ADB7D5.8070708@ti.com> References: <519E2BD4.9020906@ti.com> <20130603175108.GA11188@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130603175108.GA11188-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Greg KH Cc: Alan Stern , balbi-l0cyMroinI0@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org List-Id: devicetree@vger.kernel.org On 06/03/2013 08:51 PM, Greg KH wrote: > On Thu, May 23, 2013 at 05:46:44PM +0300, Roger Quadros wrote: >> 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. > > Then please do that. > It seems [1] went into 3.10-rc3 so this issue is fixed for 3.10. [1] https://patchwork.kernel.org/patch/2537021/ cheers, -roger -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html