Re: [S] Re: [linux-uwb] packet size problem

[Alan Stern]

On Wed, 11 Jun 2008, AntonioLin wrote:

> Hi All,
> 
> I checked srb->device->request_queue->dma_alignment in usb_stor_bulk_Bulk_transport() routine. , the value is 1023.
> 
> But in usb_stor_bulk_transfer_sglist, the length of first element in sg array is 3584 which is not divisible by 1024.
> 
> 
> Can you post your /proc/bus/usb/devices ?
> 
> I don't know how to do this, could you descript moe about it ?
> (Sorry,I have few experience about Linux.)

All you have to do is:

	cat /proc/bus/usb/devices

Or even just tell your email client to include /proc/bus/usb/devices as
an attachment.  However some Linux distributions don't automatically
mount /proc/bus/usb.  If yours doesn't, you will have to do (as root):

	mount -t usbfs none /proc/bus/usb

before you can access /proc/bus/usb/devices.  But in any case it
doesn't matter, since you have checked that the value of dma_alignment
really is 1023.

Jens, this is a question for you.  How come we're getting an SG element
whose lenth is 3584 when the request_queue's dma_alignment mask is set
to 1023?  Is dma_alignment not the right parameter to set?

Alan Stern

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