* [PATCH 1/1] Removing unncessary `usb_reset_device` on startup
@ 2014-07-16 19:31 Preston Fick
0 siblings, 0 replies; only message in thread
From: Preston Fick @ 2014-07-16 19:31 UTC (permalink / raw)
To: jhovold, gregkh, linux-usb, linux-kernel; +Cc: preston.fick
From: Preston Fick <preston.fick@silabs.com>
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>
---
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 762e4a5..6891269 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -855,9 +855,6 @@ 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;
--
1.9.1
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