From: shawn.guo@freescale.com (Shawn Guo)
To: linux-arm-kernel@lists.infradead.org
Subject: i.MX6 USB OTG support is broken on linux-next
Date: Tue, 13 May 2014 10:40:33 +0800 [thread overview]
Message-ID: <20140513024032.GK8330@dragon> (raw)
In-Reply-To: <20140513011002.GA1781@shlinux1.ap.freescale.net>
On Tue, May 13, 2014 at 09:10:36AM +0800, Li Jun wrote:
> Firstly, w/o USB_OTG and USB_OTG_FSM, your OTG port will work well as before
> (i.e. it can be host or can be gadget as you want, so it's enough for you if
> connect normal usb device or PC host), I assume you are not wanting more here,
> this dual role functionality actually is not the part of "CONFIG_USB_OTG";
Okay, I think this is why I was confused. Thanks for the clarification.
The problem is how people like me who does not know Linux USB too much
get that, considering what the help text of CONFIG_USB_OTG tells people
is just like below.
config USB_OTG
bool "OTG support"
...
help
The most notable feature of USB OTG is support for a
"Dual-Role" device, which can act as either a device
or a host. The initial role is decided by the type of
plug inserted and can be changed later when two dual
role devices talk to each other.
Select this only if your board has Mini-AB/Micro-AB
connector.
So the text tells CONFIG_USB_OTG is there for Dual-Role device support,
while you're saying the support is not the part of CONFIG_USB_OTG. As a
person who never looked at usb code, I'm completely confused here.
>
> What USB_OTG + USB_OTG_FSM does is *specific* for HNP and SRP, it's based on
> OTG spec and will *not* work well with a normal usb device, that's the reason
> behind in disable USB_OTG, which is not needed, and even impact your expecting
> function in your case...
Again, the help text of CONFIG_USB_OTG does *not* tell that.
Shawn
next prev parent reply other threads:[~2014-05-13 2:40 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-09 13:00 i.MX6 USB OTG support is broken on linux-next Shawn Guo
2014-05-10 11:10 ` Peter Chen
2014-05-10 13:18 ` Shawn Guo
2014-05-10 13:57 ` Li Jun
2014-05-11 1:34 ` Shawn Guo
2014-05-12 5:45 ` Sascha Hauer
2014-05-13 0:33 ` Peter Chen
2014-05-13 5:48 ` Sascha Hauer
2014-05-11 0:40 ` Peter Chen
2014-05-11 1:40 ` Shawn Guo
2014-05-12 1:22 ` Peter Chen
2014-05-12 13:54 ` Shawn Guo
2014-05-13 0:25 ` Peter Chen
2014-05-13 1:42 ` Shawn Guo
2014-05-13 1:10 ` Li Jun
2014-05-13 2:40 ` Shawn Guo [this message]
2014-05-13 2:40 ` Peter Chen
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=20140513024032.GK8330@dragon \
--to=shawn.guo@freescale.com \
--cc=linux-arm-kernel@lists.infradead.org \
/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