When FUNCTIONFS_EVENTFD flag is set, __ffs_data_got_descs reads a 32bits,
little-endian value right after the fixed structure header, and passes it
to eventfd_ctx_fdget. Document this.

Also, rephrase a comment to be affirmative about the role of string
descriptor at index 0. Ref: USB 2.0 spec paragraph "9.6.7 String", and
also checked to still be current in USB 3.0 spec paragraph "9.6.9 String".

Signed-off-by: Vincent Pelletier <[email protected]>
---
 drivers/usb/gadget/function/f_fs.c  | 4 ++--
 include/uapi/linux/usb/functionfs.h | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_fs.c 
b/drivers/usb/gadget/function/f_fs.c
index 17989b72cdae..2654c4f3c243 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -2091,8 +2091,8 @@ static int __ffs_data_do_entity(enum ffs_entity_type type,
 
        case FFS_STRING:
                /*
-                * Strings are indexed from 1 (0 is magic ;) reserved
-                * for languages list or some such)
+                * Strings are indexed from 1 (0 is reserved
+                * for languages list)
                 */
                if (*valuep > helper->ffs->strings_count)
                        helper->ffs->strings_count = *valuep;
diff --git a/include/uapi/linux/usb/functionfs.h 
b/include/uapi/linux/usb/functionfs.h
index acc63697a0cc..b2a31a55a612 100644
--- a/include/uapi/linux/usb/functionfs.h
+++ b/include/uapi/linux/usb/functionfs.h
@@ -93,6 +93,7 @@ struct usb_ext_prop_desc {
  * |   0 | magic     | LE32         | FUNCTIONFS_DESCRIPTORS_MAGIC_V2      |
  * |   4 | length    | LE32         | length of the whole data chunk       |
  * |   8 | flags     | LE32         | combination of functionfs_flags      |
+ * |     | eventfd   | LE32         | eventfd file descriptor              |
  * |     | fs_count  | LE32         | number of full-speed descriptors     |
  * |     | hs_count  | LE32         | number of high-speed descriptors     |
  * |     | ss_count  | LE32         | number of super-speed descriptors    |
-- 
2.11.0

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to