Some not-so-well-behaving USB hosts with a popular proprietary operating
system sometimes issue per-device requests even though they mean requests
for a particular function, e.g. for ptp (picture transfer protocol).
This patch adds optional "for_device" function in usb_configuration so that
it can be used as the last fallback when handling unknown requests. If it
is not set then the composite_setup() behaviour remains unchanged.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
---
drivers/usb/gadget/composite.c | 16 ++++++++++------
include/linux/usb/composite.h | 1 +
2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 6178353..32b0104 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1785,12 +1785,16 @@ unknown:
}
/* try the only function in the current config */
- if (!list_is_singular(&c->functions))
- goto done;
- f = list_first_entry(&c->functions, struct usb_function,
- list);
- if (f->setup)
- value = f->setup(f, ctrl);
+ if (list_is_singular(&c->functions)) {
+ f = list_first_entry(&c->functions,
+ struct usb_function, list);
+ if (f->setup)
+ value = f->setup(f, ctrl);
+ } else {
+ f = c->for_device;
+ if (f && f->setup)
+ value = f->setup(f, ctrl);
+ }
}
goto done;
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 3d87def..080aaa2 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -313,6 +313,7 @@ struct usb_configuration {
unsigned highspeed:1;
unsigned fullspeed:1;
struct usb_function *interface[MAX_CONFIG_INTERFACES];
+ struct usb_function *for_device;
};
int usb_add_config(struct usb_composite_dev *,
--
1.9.1
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