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SubjectRe: [PATCH] usbfs: Increase arbitrary limit for USB 3 isopkt length
On 05/24/2013 03:51 PM, Alan Stern wrote:
>> diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
>> index caefc80..7ac137e 100644
>> --- a/drivers/usb/core/devio.c
>> +++ b/drivers/usb/core/devio.c
>> @@ -1287,9 +1287,11 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb,
>> goto error;
>> }
>> for (totlen = u = 0; u< uurb->number_of_packets; u++) {
>> - /* arbitrary limit,
>> - * sufficient for USB 2.0 high-bandwidth iso */
>> - if (isopkt[u].length> 8192) {
>> + /* arbitrary limit need for USB 3.0
>> + * bMaxBurst (0~15 allowed, 1~16 packets)
>> + * bmAttributes (bit 1:0, mult 0~2, 1~3 packets)
>> + * sizemax: 1024 * 16 * 3 = 49152*/
>> + if (isopkt[u].length> 65536) {
>> ret = -EINVAL;
>> goto error;
>> }
> A couple of suggestions for improvements:
>
> First, new or updated multi-line comments should follow the accepted
> formatting standard:
>
> /*
> * Start comment here...
> * and end here.
> */
ok, I change the comment in the suggested way
> Second, it's confusing for the comment to mention that the limit is
> 49152 and the code to set the limit to 65536. They should agree on a
> single value (probably 49152).
>
In the USB 2 isochronous the limit is 1024 byte x 3 pkts = 3072, but in
the code is write 8192. I don't understand why, for the memory page
size? for have a tolerant limits? for rounding to a nice number?
So I wrote a limit some more big and round, but I agree with you the
best way is write the correct limit, so I modify in this way, soon.

Federico Manzan



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