From: David Brownell <david-b@pacbell.net>
To: "David S. Miller" <davem@redhat.com>
Cc: greearb@candelatech.com, jgarzik@pobox.com,
scott.feldman@intel.com, netdev@oss.sgi.com
Subject: Re: e100 "Ferguson" release
Date: Sun, 03 Aug 2003 21:08:26 -0700 [thread overview]
Message-ID: <3F2DDC3A.2040707@pacbell.net> (raw)
In-Reply-To: <20030803204642.684c6075.davem@redhat.com>
David S. Miller wrote:
> On Sun, 03 Aug 2003 20:45:01 -0700
> David Brownell <david-b@pacbell.net> wrote:
>
>
>>What can't be pre-allocated in a reliable way is the resources
>>used by the host controller drivers, specifically the transfer
>>descriptors. EHCI and OHCI usually need one per URB, unless
>>MTU is over 4 KB. UHCI normally needs quite a few.
>
>
> Ok, that's interesting.
All TDs get allocated in usb_submit_urb(), which is the first
time the "real" core of USB connects an urb with an I/O queue.
That's host-side, not device-side.
> Is there a callback that tells the USB driver that some host
> controller "resources" have become available? I mean, these host
> controllers either have to queue requests when out of resources or
> provide a callback so that the drivers can resubmit.
No such callback. If no resources, they fail -ENOMEM and the
caller must recover. Which is why hard_start_xmit() needs to
do something.
- Dave
next prev parent reply other threads:[~2003-08-04 4:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-03 4:34 e100 "Ferguson" release Feldman, Scott
2003-08-03 6:06 ` Jeff Garzik
2003-08-03 6:12 ` Jeff Garzik
2003-08-03 7:32 ` Ben Greear
2003-08-03 7:32 ` David S. Miller
2003-08-04 3:09 ` David Brownell
2003-08-04 3:08 ` David S. Miller
2003-08-04 3:45 ` David Brownell
2003-08-04 3:46 ` David S. Miller
2003-08-04 4:08 ` David Brownell [this message]
2003-08-04 4:13 ` David S. Miller
2003-08-04 17:38 ` David Brownell
2003-08-05 8:23 ` Felix Radensky
-- strict thread matches above, loose matches on Subject: below --
2003-08-05 3:45 Feldman, Scott
2003-08-05 5:29 ` Jeff Garzik
2003-08-05 7:16 ` David S. Miller
2003-08-05 14:28 Feldman, Scott
2003-08-05 15:19 Feldman, Scott
2003-08-05 15:24 ` Jeff Garzik
2003-08-10 9:00 ` Felix Radensky
2003-08-05 15:44 ` Felix Radensky
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