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Message-Id: <cover.1309710420.git.kirr@mns.spb.ru>
Date: Sun, 3 Jul 2011 20:36:55 +0400
From: Kirill Smelkov <kirr@....spb.ru>
To: Alan Stern <stern@...land.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@...ux.intel.com>,
matt mooney <mfm@...eddisk.com>,
Greg Kroah-Hartman <gregkh@...e.de>, linux-usb@...r.kernel.org,
linux-uvc-devel@...ts.berlios.de, linux-media@...r.kernel.org,
linux-kernel@...r.kernel.org, Kirill Smelkov <kirr@....spb.ru>
Subject: [PATCH v4 0/2] USB: EHCI: Allow users to override 80% max periodic bandwidth
There are cases, when 80% max isochronous bandwidth is too limiting.
Let's allow knowledgeable users to override that 80% max limit explicitly for
extreme cases, like 2 high bandwidth isochronously streaming devices on the
same High Speed USB bus in order to make them work simultaneously.
See full details in PATCH 2/2.
Changes since v3:
- as suggested by Greg KH added new entry to Documentation/ABI/;
- for consistency also touched Documentation/usb/ehci.txt reminding we now
have new setting for periodic transfers scheduler.
The base text in-there requires much updating regarding isochronous
transfers, so only "TBD" with brief description was put because I'm not the best
person to get EHCI description into shape;
- added ACK to PATCH 2/2 from Alan Stern based on previous feedback. (I hope
it's still semi-ok to put it, inspite of adding new not-reviewed text into
docs);
- minor cosmetics in patch descriptions.
Changes since v2:
- changed the copyright in ehci-sysfs from David Brownell to Alan Stern;
- added ACK to PATCH 1/2 from Alan Stern;
- inspired by concerns raised by Sarah Sharp, added more details about testing
done on N10 chipset, system stability, and that no-harm-is-done for those,
who do not change uframe_periodic_max from default 100us;
- when decreasing uframe_periodic_max, compare with the maximum number of
microseconds already allocated for any uframe, instead of stopping as soon
as it finds something above the new limit.
Changes since v1:
- dropped RFC status as "this seems like the sort of feature somebody might
reasonably want to use -- if they know exactly what they're doing";
- new preparatory patch (1/2) which moves already-in-there sysfs code into
ehci-sysfs.c;
- moved uframe_periodic_max parameter from module option to sysfs attribute,
so that it can be set per controller and at runtime, added validity checks;
- clarified a bit bandwidth analysis for 96% max periodic setup as noticed by
Alan Stern;
- clarified patch description saying that set in stone 80% max periodic is
specified by USB 2.0;
Kirill Smelkov (2):
USB: EHCI: Move sysfs related bits into ehci-sysfs.c
USB: EHCI: Allow users to override 80% max periodic bandwidth
Documentation/ABI/testing/sysfs-module | 23 ++++
Documentation/usb/ehci.txt | 2 +
drivers/usb/host/ehci-hcd.c | 11 ++-
drivers/usb/host/ehci-hub.c | 75 -------------
drivers/usb/host/ehci-sched.c | 17 +--
drivers/usb/host/ehci-sysfs.c | 190 ++++++++++++++++++++++++++++++++
drivers/usb/host/ehci.h | 2 +
7 files changed, 233 insertions(+), 87 deletions(-)
create mode 100644 drivers/usb/host/ehci-sysfs.c
--
1.7.6.rc3
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