[PATCH] usb: core: drop unnecessary le16_to_cpu() conversion

[PATCH] usb: core: drop unnecessary le16_to_cpu() conversion

[Antony Pavlov]

In drivers/usb/core/usb.c we already have le16_to_cpus() conversion
just after usb_get_descriptor():

    390     /* correct le values */
    391     le16_to_cpus(&dev->descriptor->bcdUSB);
    392     le16_to_cpus(&dev->descriptor->idVendor);
    393     le16_to_cpus(&dev->descriptor->idProduct);
    394     le16_to_cpus(&dev->descriptor->bcdDevice);

so no additional idVendor/idProduct descriptor fields
le16_to_cpu() conversion is needed after that.

On the big-endian machines extra le16_to_cpu() conversion
leads to wrong idVendor/idProduct USB device parameters values
(e.g. see devinfo <usb-device> output), and to a much more
serious problem: idVendor/idProduct-based USB device detection
does not work.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 drivers/usb/core/usb.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index f8d6014..a3fb1e8 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -445,9 +445,9 @@ int usb_new_device(struct usb_device *dev)
 	dev_add_param_fixed(&dev->dev, "Product", dev->prod);
 	dev_add_param_fixed(&dev->dev, "SerialNumber", dev->serial);
 	dev_add_param_int_ro(&dev->dev, "idVendor",
-			le16_to_cpu(dev->descriptor->idVendor), "%04x");
+			dev->descriptor->idVendor, "%04x");
 	dev_add_param_int_ro(&dev->dev, "idProduct",
-			le16_to_cpu(dev->descriptor->idProduct), "%04x");
+			dev->descriptor->idProduct, "%04x");
 	list_add_tail(&dev->list, &usb_device_list);
 	dev_count++;
 
@@ -938,11 +938,11 @@ int usb_driver_register(struct usb_driver *drv)
 static int usb_match_device(struct usb_device *dev, const struct usb_device_id *id)
 {
 	if ((id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
-	    id->idVendor != le16_to_cpu(dev->descriptor->idVendor))
+	    id->idVendor != dev->descriptor->idVendor)
 		return 0;
 
 	if ((id->match_flags & USB_DEVICE_ID_MATCH_PRODUCT) &&
-	    id->idProduct != le16_to_cpu(dev->descriptor->idProduct))
+	    id->idProduct != dev->descriptor->idProduct)
 		return 0;
 
 	return 1;
-- 
2.6.0


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Re: [PATCH] usb: core: drop unnecessary le16_to_cpu() conversion

[Sascha Hauer]

On Fri, Oct 02, 2015 at 10:23:30AM +0300, Antony Pavlov wrote:
> In drivers/usb/core/usb.c we already have le16_to_cpus() conversion
> just after usb_get_descriptor():
> 
>     390     /* correct le values */
>     391     le16_to_cpus(&dev->descriptor->bcdUSB);
>     392     le16_to_cpus(&dev->descriptor->idVendor);
>     393     le16_to_cpus(&dev->descriptor->idProduct);
>     394     le16_to_cpus(&dev->descriptor->bcdDevice);
> 
> so no additional idVendor/idProduct descriptor fields
> le16_to_cpu() conversion is needed after that.
> 
> On the big-endian machines extra le16_to_cpu() conversion
> leads to wrong idVendor/idProduct USB device parameters values
> (e.g. see devinfo <usb-device> output), and to a much more
> serious problem: idVendor/idProduct-based USB device detection
> does not work.
> 
> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
> ---
>  drivers/usb/core/usb.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Applied, thanks

Sascha

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