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Subject[PATCH v4 0/2] USB: EHCI: Allow users to override 80% max periodic bandwidth
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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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