diff options
| author |   Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 12:17:53 -0700 |
|---|---|---|
| committer | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 15:44:42 -0700 |
| commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
| tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/usb/ohci.txt | |
| parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) | |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/Documentation/usb/ohci.txt')
| -rw-r--r-- | kernel/Documentation/usb/ohci.txt | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/kernel/Documentation/usb/ohci.txt b/kernel/Documentation/usb/ohci.txt new file mode 100644 index 000000000..99320d9fa --- /dev/null +++ b/kernel/Documentation/usb/ohci.txt @@ -0,0 +1,32 @@ +23-Aug-2002 + +The "ohci-hcd" driver is a USB Host Controller Driver (HCD) that is derived +from the "usb-ohci" driver from the 2.4 kernel series. The "usb-ohci" code +was written primarily by Roman Weissgaerber <weissg@vienna.at> but with +contributions from many others (read its copyright/licencing header). + +It supports the "Open Host Controller Interface" (OHCI), which standardizes +hardware register protocols used to talk to USB 1.1 host controllers. As +compared to the earlier "Universal Host Controller Interface" (UHCI) from +Intel, it pushes more intelligence into the hardware. USB 1.1 controllers +from vendors other than Intel and VIA generally use OHCI. + +Changes since the 2.4 kernel include + + - improved robustness; bugfixes; and less overhead + - supports the updated and simplified usbcore APIs + - interrupt transfers can be larger, and can be queued + - less code, by using the upper level "hcd" framework + - supports some non-PCI implementations of OHCI + - ... more + +The "ohci-hcd" driver handles all USB 1.1 transfer types. Transfers of all +types can be queued. That was also true in "usb-ohci", except for interrupt +transfers. Previously, using periods of one frame would risk data loss due +to overhead in IRQ processing. When interrupt transfers are queued, those +risks can be minimized by making sure the hardware always has transfers to +work on while the OS is getting around to the relevant IRQ processing. + +- David Brownell + <dbrownell@users.sourceforge.net> + |