From: Preston Fick <pffick@gmail.com>
To: jhovold@gmail.com, gregkh@linuxfoundation.org,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: preston.fick@silabs.com
Subject: [PATCH 1/1] Removing unncessary `usb_reset_device` on startup
Date: Wed, 16 Jul 2014 14:31:30 -0500 [thread overview]
Message-ID: <1405539090-5682-1-git-send-email-pffick@gmail.com> (raw)
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
reply other threads:[~2014-07-16 19:31 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1405539090-5682-1-git-send-email-pffick@gmail.com \
--to=pffick@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=jhovold@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=preston.fick@silabs.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox