Re: [RFC PATCH] USB: PCI: set 32bit DMA mask for PCI based USB controllers

[Hanjun Guo <guohanjun@huawei.com>]

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