Re: [PATCH 1/1] USB: ehci-omap: Reset dma_mask pointer on probe
From: Roger Quadros
Date: Tue Jun 04 2013 - 05:48:22 EST
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  went into 3.10-rc3 so this issue is fixed for 3.10.
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