Difference between revisions of "OHCI"
(Link to OHCI document (copied from Wikipedia), known issues link, see also) |
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| − | ''' | + | '''OHCI''' (''Open Host Controller Interface'') is a standardized interface for the connection of an USB 1.1 host controller to the [[PCI]] bus. The driver for OHCI in [[ReactOS]] is ''usbohci.sys''. |
| − | + | OHCI supports USB 1.1 full and low speed devices. It does not support USB 2.0 or "high speed" devices. | |
| + | |||
| + | == Relevance for Booting == | ||
| + | |||
| + | The OHCI driver is crucial for booting. | ||
| + | |||
| + | The OHCI driver is part of the ''Critical Device Database''([http://code.reactos.org/browse/reactos/trunk/reactos/boot/bootdata/hivesys.inf?r=59461 see ''hivesys.inf'']). That means, if an OHCI device is detected in real hardware then the driver is loaded. But if the driver does not work correctly then the boot process often fails. | ||
| + | |||
| + | == Source code == | ||
| + | |||
| + | The path for the source code of ''usbohci.sys'' is [http://code.reactos.org/browse/reactos/trunk/reactos/drivers/usb/usbohci /reactos/drivers/usb/usbohci/]. | ||
| + | |||
| + | For high level functionality of the driver the ''[[libusb]]'' is used ([http://code.reactos.org/browse/reactos/trunk/reactos/lib/drivers/libusb reactos/lib/drivers/libusb]). Thus changes in ''libusb'' influence the functionality ''usbohci.sys''. | ||
| + | |||
| + | == Known issues == | ||
| − | |||
* [http://jira.reactos.org/issues/?jql=text%20~%20%22OHCI%22 ReactOS Jira query for OHCI] | * [http://jira.reactos.org/issues/?jql=text%20~%20%22OHCI%22 ReactOS Jira query for OHCI] | ||
| + | * [http://jira.reactos.org/issues/?jql=cf%5B10400%5D%20%3D%20usbohci ReactOS Jira query for module ''usbohci''] | ||
| − | ==See also== | + | == See also == |
* [[USB]] | * [[USB]] | ||
* [[UHCI]] (USB 1.1) | * [[UHCI]] (USB 1.1) | ||
* [[EHCI]] (USB 2.0) | * [[EHCI]] (USB 2.0) | ||
| − | ==External links== | + | == External links == |
| − | *Wikipedia: [ | + | *Wikipedia: [[wikipedia:Host controller interface (USB, Firewire)#Open Host Controller Interface 2|Open Host Controller Interface]] |
*[ftp://ftp.compaq.com/pub/supportinformation/papers/hcir1_0a.pdf An OHCI for USB standard document from Compaq, Microsoft and National Semiconductor] (PDF) | *[ftp://ftp.compaq.com/pub/supportinformation/papers/hcir1_0a.pdf An OHCI for USB standard document from Compaq, Microsoft and National Semiconductor] (PDF) | ||
| − | + | [[Category:ReactOS Components]] | |
| − | [[Category: | ||
Latest revision as of 12:04, 3 June 2014
OHCI (Open Host Controller Interface) is a standardized interface for the connection of an USB 1.1 host controller to the PCI bus. The driver for OHCI in ReactOS is usbohci.sys.
OHCI supports USB 1.1 full and low speed devices. It does not support USB 2.0 or "high speed" devices.
Relevance for Booting
The OHCI driver is crucial for booting.
The OHCI driver is part of the Critical Device Database(see hivesys.inf). That means, if an OHCI device is detected in real hardware then the driver is loaded. But if the driver does not work correctly then the boot process often fails.
Source code
The path for the source code of usbohci.sys is /reactos/drivers/usb/usbohci/.
For high level functionality of the driver the libusb is used (reactos/lib/drivers/libusb). Thus changes in libusb influence the functionality usbohci.sys.
