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From: Greg KH <gregkh@linuxfoundation.org>
To: JC Kuo <jckuo@nvidia.com>
Cc: linux-usb@vger.kernel.org, stern@rowland.harvard.edu,
	usb-storage@lists.one-eyed-alien.net, oneukum@suse.com
Subject: Re: [PATCH] usb: storage: skip only when uas driver is loaded
Date: Mon, 1 Jul 2019 10:52:48 +0200	[thread overview]
Message-ID: <20190701085248.GA28681@kroah.com> (raw)
In-Reply-To: <20190701084848.32502-1-jckuo@nvidia.com>

On Mon, Jul 01, 2019 at 04:48:48PM +0800, JC Kuo wrote:
> When usb-storage driver detects a UAS capable device, it ignores the
> device if CONFIG_USB_UAS is enabled. usb-storage driver assumes uas
> driver certainly will be loaded. However, it's possible that uas
> driver will not be loaded, for example, uas kernel module is not
> installed properly or it is in modprobe blacklist.
> 
> In case of uas driver not being loaded, the UAS capable device will
> not fallback to work at Bulk-only-transfer mode. The device just
> disappears without any notification to user/userspace.
> 
> This commit changes usb-storage driver to skip UAS capable device
> only when uas driver is already loaded to make sure the device will
> at least work with Bulk protocol.

But what happens if the driver is loaded afterward, because 'modprobe'
was called by the driver core (or it should have been, because this is a
device that supports that protocol)?

I think you just broke working systems :(

Why wouldn't the UAS driver get loaded automatically if it is configured
in the system as it is today?

thanks,

greg k-h

  reply	other threads:[~2019-07-01  8:52 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-01  8:48 [PATCH] usb: storage: skip only when uas driver is loaded JC Kuo
2019-07-01  8:52 ` Greg KH [this message]
2019-07-02  2:36   ` JC Kuo
2019-07-02  4:42     ` Greg KH
2019-07-02  5:29       ` JC Kuo
2019-07-02  6:56         ` JC Kuo
2019-07-02  7:34           ` Greg KH
2019-07-02  7:57             ` JC Kuo
2019-07-02  8:14               ` Greg KH
2019-07-02  9:11           ` Oliver Neukum
2019-07-02 14:05             ` JC Kuo
2019-07-02 15:29               ` Oliver Neukum
2019-07-02  6:53     ` Oliver Neukum

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