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Subject: Re: [RFC PATCH] USB: PCI: set 32bit DMA mask for PCI based USB
 controllers
To:     Christoph Hellwig <hch@lst.de>
CC:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Bjorn Helgaas <helgaas@kernel.org>,
        <linux-usb@vger.kernel.org>, <linux-acpi@vger.kernel.org>,
        <linux-pci@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linuxarm@huawei.com>, John Garry <john.garry@huawei.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        <anthony.jebson@huawei.com>, Hanjun Guo <hanjun.guo@linaro.org>
References: <1548831714-3706-1-git-send-email-guohanjun@huawei.com>
 <20190130074059.GA29458@lst.de>
From:   Hanjun Guo <guohanjun@huawei.com>
Message-ID: <b42f939d-8946-4865-59d8-7451d7d753bd@huawei.com>
Date:   Thu, 31 Jan 2019 09:19:14 +0800
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Hi Christoph,

On 2019/1/30 15:40, Christoph Hellwig wrote:
> On Wed, Jan 30, 2019 at 03:01:54PM +0800, Hanjun Guo wrote:
>> This is the RFC version, I'm not sure this is the best solution,
>> comments are warmly welcomed.
>>
>> Thanks
>> Hanjun
>>
>>  drivers/usb/core/hcd-pci.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
>> index 0343246..a9c33e6 100644
>> --- a/drivers/usb/core/hcd-pci.c
>> +++ b/drivers/usb/core/hcd-pci.c
>> @@ -188,6 +188,10 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>>  	if (pci_enable_device(dev) < 0)
>>  		return -ENODEV;
>>  
>> +	retval = dma_coerce_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32));
>> +	if (retval)
>> +		return retval;
> 
> dma_coerce_mask_and_coherent is only for platform devices (and I'm
> not sure it is a good idea to start with, but that is a different
> story).

Yes, that's why this is the RFC version.

> 
> PCI device should have the dma_mask pointer set already, so you should
> use dma_set_mask_and_coherent here.

I will wait for a while to see if more comments, if not, I will update
my patch as you suggested.

Thanks
Hanjun