From: Oliver Neukum <oliver@neukum.org>
To: linux-usb-devel@lists.sourceforge.net
Subject: Re: [linux-usb-devel] [PATCH] USB: Only enable autosuspend by default on certain device classes
Date: Fri, 3 Aug 2007 09:57:45 +0200
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Cc: Matthew Garrett <mjg59@srcf.ucam.org>, Greg KH <gregkh@suse.de>,
       linux-kernel@vger.kernel.org
References: <20070802235613.GA9487@srcf.ucam.org> <20070803011505.GA32589@suse.de> <20070803014756.GA10392@srcf.ucam.org>
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Am Freitag 03 August 2007 schrieb Matthew Garrett:
> > Also, we have udev rules for SANE that disables their autosuspend
> > settings, which handles the majority of the devices we have seen with
> > problems.
> 
> Several printers seem to have the issue as well, and the blacklist seems 
> to contain some odd miscellaneous devices like the Blackberry. The main

Then make autosuspend support for the printer driver a config option.
This is not a reason to change the core usb code. The core code needs
to be involved only for device that are driven through usbfs. The major types
are:

- scanners
- PTP devices
- OBEX

Scanners are covered by SANE's latest CVS
PTP are a class and could be covered by a single udev rule
Obex is comm, so the patch wouldn't help.

> concern I have is that kernel developers just don't tend to be the sort 
> of people that use webcams, printers or scanners, so we're relying on 
> normal users to go to the effort of reporting that their device has 
> stopped working.

Kernel developers are a diverser lot than you think ;-)
We don't enable autosuspend in drivers we can't test, except where
the lack of a kernel driver forces us to use a broad swipe. Printers
were tested, too, and most printers seem to work.

	Regards
		Oliver
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