* [PATCH] usbfs: Increase arbitrary limit for USB 3 isopkt length
@ 2013-05-24 8:47 Federico Manzan
2013-05-24 13:51 ` Alan Stern
2013-05-24 14:46 ` Sergei Shtylyov
0 siblings, 2 replies; 4+ messages in thread
From: Federico Manzan @ 2013-05-24 8:47 UTC (permalink / raw)
To: gregkh; +Cc: sarah.a.sharp, stern, linux-usb, linux-kernel, Federico Manzan
Increase the current arbitrary limit for isocronous packet size to a
value large enough to account for USB 3.0 super bandwidth streams,
bMaxBurst (0~15 allowed, 1~16 packets)
bmAttributes (bit 1:0, mult 0~2, 1~3 packets)
so the size max for one USB 3 isocronous transfer is
1024 byte * 16 * 3 = 49152 byte
Signed-off-by: Federico Manzan <f.manzan@gmail.com>
---
drivers/usb/core/devio.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
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;
}
--
1.7.10.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] usbfs: Increase arbitrary limit for USB 3 isopkt length
2013-05-24 8:47 [PATCH] usbfs: Increase arbitrary limit for USB 3 isopkt length Federico Manzan
@ 2013-05-24 13:51 ` Alan Stern
2013-05-24 15:36 ` Federico Manzan
2013-05-24 14:46 ` Sergei Shtylyov
1 sibling, 1 reply; 4+ messages in thread
From: Alan Stern @ 2013-05-24 13:51 UTC (permalink / raw)
To: Federico Manzan; +Cc: gregkh, sarah.a.sharp, linux-usb, linux-kernel
On Fri, 24 May 2013, Federico Manzan wrote:
> Increase the current arbitrary limit for isocronous packet size to a
> value large enough to account for USB 3.0 super bandwidth streams,
> bMaxBurst (0~15 allowed, 1~16 packets)
> bmAttributes (bit 1:0, mult 0~2, 1~3 packets)
> so the size max for one USB 3 isocronous transfer is
> 1024 byte * 16 * 3 = 49152 byte
>
> Signed-off-by: Federico Manzan <f.manzan@gmail.com>
So you decided to take matters into your own hands. Good for you!
> 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.
*/
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).
If you make those two changes, you can add
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Alan Stern
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] usbfs: Increase arbitrary limit for USB 3 isopkt length
2013-05-24 13:51 ` Alan Stern
@ 2013-05-24 15:36 ` Federico Manzan
0 siblings, 0 replies; 4+ messages in thread
From: Federico Manzan @ 2013-05-24 15:36 UTC (permalink / raw)
To: Alan Stern; +Cc: gregkh, sarah.a.sharp, linux-usb, linux-kernel
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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] usbfs: Increase arbitrary limit for USB 3 isopkt length
2013-05-24 8:47 [PATCH] usbfs: Increase arbitrary limit for USB 3 isopkt length Federico Manzan
2013-05-24 13:51 ` Alan Stern
@ 2013-05-24 14:46 ` Sergei Shtylyov
1 sibling, 0 replies; 4+ messages in thread
From: Sergei Shtylyov @ 2013-05-24 14:46 UTC (permalink / raw)
To: Federico Manzan; +Cc: gregkh, sarah.a.sharp, stern, linux-usb, linux-kernel
Hello.
On 24-05-2013 12:47, Federico Manzan wrote:
> Increase the current arbitrary limit for isocronous packet size to a
> value large enough to account for USB 3.0 super bandwidth streams,
> bMaxBurst (0~15 allowed, 1~16 packets)
> bmAttributes (bit 1:0, mult 0~2, 1~3 packets)
> so the size max for one USB 3 isocronous transfer is
> 1024 byte * 16 * 3 = 49152 byte
> Signed-off-by: Federico Manzan <f.manzan@gmail.com>
> ---
> drivers/usb/core/devio.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
> 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*/
The preferred style of the multi-line comments is this:
/*
* bla
* bla
*/
WBR, Sergei
^ permalink raw reply [flat|nested] 4+ messages in thread
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2013-05-24 8:47 [PATCH] usbfs: Increase arbitrary limit for USB 3 isopkt length Federico Manzan
2013-05-24 13:51 ` Alan Stern
2013-05-24 15:36 ` Federico Manzan
2013-05-24 14:46 ` Sergei Shtylyov
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