From: Greg KH <gregkh@linuxfoundation.org>
To: Hans Beckerus <hans.beckerus@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>, linux-serial@vger.kernel.org
Subject: Re: USB serial support / Prolific PL2303 Driver
Date: Mon, 8 Apr 2013 11:19:28 -0700 [thread overview]
Message-ID: <20130408181928.GA7880@kroah.com> (raw)
In-Reply-To: <5162FFF5.6040403@gmail.com>
On Mon, Apr 08, 2013 at 07:35:49PM +0200, Hans Beckerus wrote:
> >USB starts as one of the last things in the kernel boot process, so the
> >best you can ever get is a summary of what happened during the boot, not
> >the kernel boot messages as they happen because they happen before the
> >USB device is initialized.
> Sure. That is an acceptable limitation. However, I wonder if this
> will be different once we get U-Boot USB console support on this
> platform?
> Question though is if Linux ever will be able to benefit from a
> first stage driver already being kicked-off by U-Boot.
For USB, no, that can't really happen, as the whole USB stack has to be
started up "from scratch" after u-boot starts Linux up. There's no way
that Linux can take a "already discovered" usb stack and continue it's
usage.
Unless you possibly use Linux for your bootloader, and if so, in that
case, you don't need u-boot, and only do all device discovery once,
which is the ideal thing from a speed standpoint.
Good luck,
greg k-h
prev parent reply other threads:[~2013-04-08 18:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-08 13:37 USB serial support / Prolific PL2303 Driver Hans Beckérus
2013-04-08 15:03 ` Greg KH
2013-04-08 15:06 ` Re[2]: " Alexander Shiyan
2013-04-08 15:57 ` Hans Beckérus
2013-04-08 16:03 ` Greg KH
2013-04-08 16:20 ` Hans Beckérus
2013-04-08 16:29 ` Greg KH
2013-04-08 17:35 ` Hans Beckerus
2013-04-08 18:19 ` Greg KH [this message]
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