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 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 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 + 5 files changed, 208 insertions(+), 87 deletions(-) create mode 100644 drivers/usb/host/ehci-sysfs.c -- 1.7.6.rc3 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
