[PATCH v3 2/2] usb: webcam: Invalid size of Processing Unit Descriptor

From: Pawel Laszczak
Date: Mon Mar 15 2021 - 03:01:44 EST


From: Pawel Laszczak <pawell@xxxxxxxxxxx>

According with USB Device Class Definition for Video Device the
Processing Unit Descriptor bLength should be 12 (10 + bmControlSize),
but it has 11.

Invalid length caused that Processing Unit Descriptor Test Video form
CV tool failed. To fix this issue patch adds bmVideoStandards into
uvc_processing_unit_descriptor structure.

The bmVideoStandards field was added in UVC 1.1 and it wasn't part of
UVC 1.0a.

Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>

---
Changelog:
v3:
- updated the commit message
- added bmVideoStandard field to UVC gadget driver
v2:
- updated UVC_DT_PROCESSING_UNIT_SIZE macro

drivers/usb/gadget/function/f_uvc.c | 1 +
drivers/usb/gadget/legacy/webcam.c | 1 +
include/uapi/linux/usb/video.h | 3 ++-
3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 5d62720bb9e1..e3b0a79c8f01 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -823,6 +823,7 @@ static struct usb_function_instance *uvc_alloc_inst(void)
pd->bmControls[0] = 1;
pd->bmControls[1] = 0;
pd->iProcessing = 0;
+ pd->bmVideoStandards = 0;

od = &opts->uvc_output_terminal;
od->bLength = UVC_DT_OUTPUT_TERMINAL_SIZE;
diff --git a/drivers/usb/gadget/legacy/webcam.c b/drivers/usb/gadget/legacy/webcam.c
index 3a61de4bb2b1..accb4dacf715 100644
--- a/drivers/usb/gadget/legacy/webcam.c
+++ b/drivers/usb/gadget/legacy/webcam.c
@@ -125,6 +125,7 @@ static const struct uvc_processing_unit_descriptor uvc_processing = {
.bmControls[0] = 1,
.bmControls[1] = 0,
.iProcessing = 0,
+ .bmVideoStandrads = 0,
};

static const struct uvc_output_terminal_descriptor uvc_output_terminal = {
diff --git a/include/uapi/linux/usb/video.h b/include/uapi/linux/usb/video.h
index d854cb19c42c..bfdae12cdacf 100644
--- a/include/uapi/linux/usb/video.h
+++ b/include/uapi/linux/usb/video.h
@@ -302,9 +302,10 @@ struct uvc_processing_unit_descriptor {
__u8 bControlSize;
__u8 bmControls[2];
__u8 iProcessing;
+ __u8 bmVideoStandards;
} __attribute__((__packed__));

-#define UVC_DT_PROCESSING_UNIT_SIZE(n) (9+(n))
+#define UVC_DT_PROCESSING_UNIT_SIZE(n) (10+(n))

/* 3.7.2.6. Extension Unit Descriptor */
struct uvc_extension_unit_descriptor {
--
2.25.1