Got it! Thanks~
Another problem: Do i need free all of the urbs which i have built before in my
diconnect function? Now i just free one urb in my func.
For example:
struct urb *myurb;
my_prob()
{...
for(i=0; i<5; i++)
{
myurb = usb_alloc_urb(0);
FILL_BULK_UBR(myurb,..............);
usb_submit_urb(myurb);
}...
}
my_disconnect(myurb)
{...
usb_unlink_urb(myusb);
usb_free_urb(myurb);...
}
Thanks again!
Levis
-----Original Message-----
From: Alan Stern [mailto:[EMAIL PROTECTED]
Sent: Thursday, December 02, 2004 4:27 AM
To: Xu Levis-Q16136
Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: RE: An usb host transfer speed issue, could anybodies help me or give
me some advice?
On Wed, 1 Dec 2004, Xu Levis-Q16136 wrote:
> Alan/Anybodies,
> Now I build 10 URB(IN) and sent them in my prob function, then sent the
> remaining URBs from the completion callback. The transfer speed is about
> 650K bytes/second, good speed. Another issue, do you think this way is
> suit for BULK_OUT transfer? The test result is same as before when i
> build 5 URB(OUT) and sent my bulkusb_write function.
The same principle should work for both bulk-in and bulk-out. However the
optimum number and size of the URBs will vary from system to system. You
should experiment to see what combination works best on your computer.
Alan Stern
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