From: Mark Lord <lkml@rtr.ca>
To: Andrew Morton <akpm@osdl.org>
Cc: David Liontooth <liontooth@cogweb.net>,
linux-kernel@vger.kernel.org,
linux-usb-devel@lists.sourceforge.net,
Alan Stern <stern@rowland.harvard.edu>
Subject: Re: USB devices fail unnecessarily on unpowered hubs
Date: Thu, 01 Jun 2006 13:34:46 -0400 [thread overview]
Message-ID: <447F2536.9030904@rtr.ca> (raw)
In-Reply-To: <20060601030140.172239b0.akpm@osdl.org>
Andrew Morton wrote:
> On Thu, 01 Jun 2006 02:18:20 -0700
> ..
>> This is generating a lot of grief and appears to be unnecessarily
>> strict. Common USB sticks with a MaxPower value just above 100mA, for
>> instance, typically work fine on unpowered hubs supplying 100mA.
>>
>> Is a more user-friendly solution possible? Could the shortfall
>> information be passed to udev, which would allow rules to be written per
>> device?
..
> Yes, it sounds like we're being non-real-worldly here. This change
> apparently broke things. Did it actually fix anything as well?
I think a far more sensible approach would be to just ensure that the
total current draw for the (unpowered) hub and all connected devices,
stays below the 500mA allowed. So a 200mA device could coexist with
a 100mA device on a hub which itself steals 100mA.
Cheers
next prev parent reply other threads:[~2006-06-01 17:34 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-01 9:18 USB devices fail unnecessarily on unpowered hubs David Liontooth
2006-05-30 20:01 ` Pavel Machek
2006-06-03 9:29 ` Oliver Neukum
2006-06-05 14:32 ` [linux-usb-devel] " David Brownell
2006-06-06 7:43 ` Oliver Neukum
2006-06-08 7:01 ` Pavel Machek
2006-06-08 8:34 ` [PATCH] limit power budget on spitz Pavel Machek
2006-06-08 8:50 ` Richard Purdie
2006-06-08 9:02 ` Pavel Machek
2006-06-08 9:22 ` Richard Purdie
2006-06-08 17:09 ` Russell King
2006-06-08 18:26 ` David Brownell
2006-06-08 20:06 ` Richard Purdie
2006-06-08 20:38 ` [linux-usb-devel] " David Brownell
2006-06-08 21:22 ` Richard Purdie
2006-06-08 21:40 ` David Brownell
2006-06-08 21:49 ` Richard Purdie
2006-06-08 23:44 ` David Brownell
2006-06-09 1:25 ` Nicolas Pitre
2006-06-09 2:03 ` David Brownell
2006-06-09 2:34 ` Nicolas Pitre
2006-06-01 10:01 ` USB devices fail unnecessarily on unpowered hubs Andrew Morton
2006-06-01 11:42 ` Daniel Drake
2006-06-01 14:58 ` Alan Stern
2006-06-01 15:09 ` linux-os (Dick Johnson)
2006-06-01 15:23 ` Lennart Sorensen
2006-06-01 21:39 ` Dagfinn Ilmari Mannsåker
2006-06-01 15:53 ` Oliver Neukum
2006-06-01 17:24 ` linux-os (Dick Johnson)
2006-06-01 16:57 ` Alan Stern
2006-06-01 16:43 ` [linux-usb-devel] " Greg KH
2006-06-02 0:03 ` David Liontooth
2006-06-02 1:53 ` [linux-usb-devel] " David Brownell
2006-06-02 7:12 ` Oliver Neukum
2006-06-02 15:11 ` Alan Stern
2006-06-02 19:49 ` David Liontooth
2006-06-01 16:59 ` Andrew Morton
2006-06-01 17:08 ` Alan Stern
2006-06-01 17:34 ` Mark Lord [this message]
2006-06-01 17:47 ` Alan Stern
[not found] <6iWP5-2gj-71@gated-at.bofh.it>
[not found] ` <6iX82-2UJ-3@gated-at.bofh.it>
2006-06-01 23:35 ` Robert Hancock
2006-06-01 23:46 ` Randy.Dunlap
[not found] <6iYGP-5hv-3@gated-at.bofh.it>
[not found] ` <6iYQx-5Jc-7@gated-at.bofh.it>
2006-06-01 23:37 ` Robert Hancock
-- strict thread matches above, loose matches on Subject: below --
2006-06-05 11:07 Lee Dowling
[not found] <6kl8h-1Uf-15@gated-at.bofh.it>
2006-06-07 0:51 ` Robert Hancock
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