Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 3.12 03/56] USB: serial: cp210x: Removing unncessary `usb_reset_device` on startup | Date | Wed, 3 Sep 2014 11:26:22 +0200 |
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From: Preston Fick <preston.fick@silabs.com>
3.12-stable review patch. If anyone has any objections, please let me know.
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commit 934ef5aca9daea10507eebcbd0fb8f6d57d55359 upstream.
This `usb_reset_device` command has been around since the driver was originally reverse engineered. It doesn't cause much issue on single interface CP210x devices, but on the CP2105 and CP2108 with 2 and 4 interfaces respectively it will cause instability on enumeration and delays enumeration noticably. There should be no reason to reset a device at startup, per the CP210x AN571 spec.
Signed-off-by: Preston Fick <preston.fick@silabs.com> Cc: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- drivers/usb/serial/cp210x.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 1db213a6e843..e5ac744ac73f 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -860,9 +860,6 @@ static int cp210x_startup(struct usb_serial *serial) struct usb_host_interface *cur_altsetting; struct cp210x_serial_private *spriv; - /* cp210x buffers behave strangely unless device is reset */ - usb_reset_device(serial->dev); - spriv = kzalloc(sizeof(*spriv), GFP_KERNEL); if (!spriv) return -ENOMEM; -- 2.1.0
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