diff mbox series

usb: gadget: uvc: add bInterval checking for HS mode

Message ID 20210304104515.35933-1-pawell@gli-login.cadence.com
State New
Headers show
Series usb: gadget: uvc: add bInterval checking for HS mode | expand

Commit Message

Pawel Laszczak March 4, 2021, 10:45 a.m. UTC 
From: Pawel Laszczak <pawell@cadence.com>

Patch adds extra checking for bInterval passed by configfs.
The 5.6.4 chapter of USB Specification (rev. 2.0) say:
"A high-bandwidth endpoint must specify a period of 1x125 µs
(i.e., a bInterval value of 1)."

The issue was observed during testing UVC class on CV.
I treat this change as improvement because we can control
bInterval by configfs.

Signed-off-by: Pawel Laszczak <pawell@cadence.com>
---
 drivers/usb/gadget/function/f_uvc.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Pawel Laszczak March 8, 2021, 8:28 a.m. UTC | #1 
>

>On Fri, Mar 5, 2021 at 12:40 AM Pawel Laszczak <mailto:pawell@cadence.com> wrote:

>From: Pawel Laszczak <mailto:pawell@cadence.com>

>

>Patch adds extra checking for bInterval passed by configfs.

>The 5.6.4 chapter of USB Specification (rev. 2.0) say:

>"A high-bandwidth endpoint must specify a period of 1x125 µs

>(i.e., a bInterval value of 1)."

>

>The issue was observed during testing UVC class on CV.

>I treat this change as improvement because we can control

>bInterval by configfs.

>

>Signed-off-by: Pawel Laszczak <mailto:pawell@cadence.com>

>---

> drivers/usb/gadget/function/f_uvc.c | 6 ++++++

> 1 file changed, 6 insertions(+)

>

>diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c

>index 44b4352a2676..5d62720bb9e1 100644

>--- a/drivers/usb/gadget/function/f_uvc.c

>+++ b/drivers/usb/gadget/function/f_uvc.c

>@@ -631,6 +631,12 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)

>                cpu_to_le16(min(opts->streaming_maxpacket, 1023U));

>        uvc_fs_streaming_ep.bInterval = opts->streaming_interval;

>

>+       /* A high-bandwidth endpoint must specify a bInterval value of 1 */

>+       if (max_packet_mult > 1)

>+               uvc_hs_streaming_ep.bInterval = 1;

>+       else

>+               uvc_hs_streaming_ep.bInterval = opts->streaming_interval;

>+

>

>There is a "uvc_hs_streaming_ep.bInterval = opts->streaming_interval;" again at below code

>Besides, the default value is 1 for opts->streaming_interval. What the real issue you observed

>at CV test?

>


The issue occurs when I intentionally set:
        echo 3072  > functions/$FUNCTION/streaming_maxpacket
        echo 4 > functions/$FUNCTION/streaming_interval

Then for  CV CH9 TD 9.5: Endpoint Descriptor test it got:
"(Mult = 2)Illegal high speed isochronous endpoint MaxPacketSize : 0x400
(USB: 1.2.78) A High speed Interrupt/Isochronous endpoint must have a MaxPacketSize between
683 and 1024 and bInterval value of 1 when the Mult value is two."

For default value CV passed.  Of course, I can fix it by changing  streaming_interval, but I thought that
it could be good to have protection against this issue. 
Especially since Usb 2 specification say that bInterval must be 1 for high bandwidth endpoints.

Pawel

>Peter

>

>        uvc_hs_streaming_ep.wMaxPacketSize =

>                cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));

>        uvc_hs_streaming_ep.bInterval = opts->streaming_interval;

>--

>2.25.1
Pawel Laszczak March 8, 2021, 12:59 p.m. UTC | #2 
Peter,

You're right. This patch is wrong. I didn't remove the "uvc_hs_streaming_ep.bInterval"
assignment. 

It has been fixed in v2.

Pawel

>>

>>On Fri, Mar 5, 2021 at 12:40 AM Pawel Laszczak <mailto:pawell@cadence.com> wrote:

>>From: Pawel Laszczak <mailto:pawell@cadence.com>

>>

>>Patch adds extra checking for bInterval passed by configfs.

>>The 5.6.4 chapter of USB Specification (rev. 2.0) say:

>>"A high-bandwidth endpoint must specify a period of 1x125 µs

>>(i.e., a bInterval value of 1)."

>>

>>The issue was observed during testing UVC class on CV.

>>I treat this change as improvement because we can control

>>bInterval by configfs.

>>

>>Signed-off-by: Pawel Laszczak <mailto:pawell@cadence.com>

>>---

>> drivers/usb/gadget/function/f_uvc.c | 6 ++++++

>> 1 file changed, 6 insertions(+)

>>

>>diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c

>>index 44b4352a2676..5d62720bb9e1 100644

>>--- a/drivers/usb/gadget/function/f_uvc.c

>>+++ b/drivers/usb/gadget/function/f_uvc.c

>>@@ -631,6 +631,12 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)

>>                cpu_to_le16(min(opts->streaming_maxpacket, 1023U));

>>        uvc_fs_streaming_ep.bInterval = opts->streaming_interval;

>>

>>+       /* A high-bandwidth endpoint must specify a bInterval value of 1 */

>>+       if (max_packet_mult > 1)

>>+               uvc_hs_streaming_ep.bInterval = 1;

>>+       else

>>+               uvc_hs_streaming_ep.bInterval = opts->streaming_interval;

>>+

>>

>>There is a "uvc_hs_streaming_ep.bInterval = opts->streaming_interval;" again at below code

>>Besides, the default value is 1 for opts->streaming_interval. What the real issue you observed

>>at CV test?

>>

>

>The issue occurs when I intentionally set:

>        echo 3072  > functions/$FUNCTION/streaming_maxpacket

>        echo 4 > functions/$FUNCTION/streaming_interval

>

>Then for  CV CH9 TD 9.5: Endpoint Descriptor test it got:

>"(Mult = 2)Illegal high speed isochronous endpoint MaxPacketSize : 0x400

>(USB: 1.2.78) A High speed Interrupt/Isochronous endpoint must have a MaxPacketSize between

>683 and 1024 and bInterval value of 1 when the Mult value is two."

>

>For default value CV passed.  Of course, I can fix it by changing  streaming_interval, but I thought that

>it could be good to have protection against this issue.

>Especially since Usb 2 specification say that bInterval must be 1 for high bandwidth endpoints.

>

>Pawel

>

>>Peter

>>

>>        uvc_hs_streaming_ep.wMaxPacketSize =

>>                cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));

>>        uvc_hs_streaming_ep.bInterval = opts->streaming_interval;

>>--

>>2.25.1


Thanks,
Pawel Laszczak
Pawel Laszczak March 10, 2021, 5:45 a.m. UTC | #3 
Please check whether the problem occurs in this fragment of code:
https://elixir.bootlin.com/linux/latest/source/drivers/usb/cdns3/gadget.c#L2569

zlp_buff is allocated with kzalloc.

Pawel

>>On Fri, Mar 5, 2021 at 12:40 AM Pawel Laszczak <mailto:pawell@cadence.com> wrote:

>>From: Pawel Laszczak <mailto:pawell@cadence.com>

>>

>>Patch adds extra checking for bInterval passed by configfs.

>>The 5.6.4 chapter of USB Specification (rev. 2.0) say:

>>"A high-bandwidth endpoint must specify a period of 1x125 µs

>>(i.e., a bInterval value of 1)."

>>

>>The issue was observed during testing UVC class on CV.

>>I treat this change as improvement because we can control

>>bInterval by configfs.

>>

>>Signed-off-by: Pawel Laszczak <mailto:pawell@cadence.com>

>>---

>> drivers/usb/gadget/function/f_uvc.c | 6 ++++++

>> 1 file changed, 6 insertions(+)

>>

>>diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c

>>index 44b4352a2676..5d62720bb9e1 100644

>>--- a/drivers/usb/gadget/function/f_uvc.c

>>+++ b/drivers/usb/gadget/function/f_uvc.c

>>@@ -631,6 +631,12 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)

>>                cpu_to_le16(min(opts->streaming_maxpacket, 1023U));

>>        uvc_fs_streaming_ep.bInterval = opts->streaming_interval;

>>

>>+       /* A high-bandwidth endpoint must specify a bInterval value of 1 */

>>+       if (max_packet_mult > 1)

>>+               uvc_hs_streaming_ep.bInterval = 1;

>>+       else

>>+               uvc_hs_streaming_ep.bInterval = opts->streaming_interval;

>>+

>>

>>There is a "uvc_hs_streaming_ep.bInterval = opts->streaming_interval;" again at below code

>>Besides, the default value is 1 for opts->streaming_interval. What the real issue you observed

>>at CV test?

>>

>

>The issue occurs when I intentionally set:

>        echo 3072  > functions/$FUNCTION/streaming_maxpacket

>        echo 4 > functions/$FUNCTION/streaming_interval

>

>Then for  CV CH9 TD 9.5: Endpoint Descriptor test it got:

>"(Mult = 2)Illegal high speed isochronous endpoint MaxPacketSize : 0x400

>(USB: 1.2.78) A High speed Interrupt/Isochronous endpoint must have a MaxPacketSize between

>683 and 1024 and bInterval value of 1 when the Mult value is two."

>

>For default value CV passed.  Of course, I can fix it by changing  streaming_interval, but I thought that

>it could be good to have protection against this issue.

>Especially since Usb 2 specification say that bInterval must be 1 for high bandwidth endpoints.

>

>Pawel

>

>>Peter

>>

>>        uvc_hs_streaming_ep.wMaxPacketSize =

>>                cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));

>>        uvc_hs_streaming_ep.bInterval = opts->streaming_interval;

>>--

>>2.25.1
diff mbox series

Patch

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 44b4352a2676..5d62720bb9e1 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -631,6 +631,12 @@  uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 		cpu_to_le16(min(opts->streaming_maxpacket, 1023U));
 	uvc_fs_streaming_ep.bInterval = opts->streaming_interval;
 
+	/* A high-bandwidth endpoint must specify a bInterval value of 1 */
+	if (max_packet_mult > 1)
+		uvc_hs_streaming_ep.bInterval = 1;
+	else
+		uvc_hs_streaming_ep.bInterval = opts->streaming_interval;
+
 	uvc_hs_streaming_ep.wMaxPacketSize =
 		cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));
 	uvc_hs_streaming_ep.bInterval = opts->streaming_interval;