Searched hist:"001 b0c78" (Results 1 – 2 of 2) sorted by relevance
| /openbmc/linux/Documentation/ABI/testing/ |
| H A D | sysfs-driver-typec-displayport | 001b0c78 Sun Dec 11 13:37:55 CST 2022 Badhri Jagan Sridharan <badhri@google.com> usb: typec: altmodes/displayport: Add hpd sysfs attribute
Exporsing HotPlugDetect(HPD) helps userspace to infer HPD
state as defined by VESA DisplayPort Alt Mode on USB Type-C Standard.
This allows userspace to notify users for self help, for instance,
to hint user that the display port cable is probably detached (or)
the display port sink (viz., monitors ect.,) is un-powered.
Also helps to debug issues reported from field.
This change adds an additional attribute "hpd" to the existing
"displayport" attributes.
VESA DisplayPort Alt Mode on USB Type-C Standard defines how
HotPlugDetect(HPD) shall be supported on the USB-C connector
when operating in DisplayPort Alt Mode. This is a read only
node which reflects the current state of HPD.
Valid values:
- 1 when HPD’s logical state is high (HPD_High)
- 0 when HPD’s logical state is low (HPD_Low)
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20221211193755.1392128-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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| /openbmc/linux/drivers/usb/typec/altmodes/ |
| H A D | displayport.c | 001b0c78 Sun Dec 11 13:37:55 CST 2022 Badhri Jagan Sridharan <badhri@google.com> usb: typec: altmodes/displayport: Add hpd sysfs attribute
Exporsing HotPlugDetect(HPD) helps userspace to infer HPD
state as defined by VESA DisplayPort Alt Mode on USB Type-C Standard.
This allows userspace to notify users for self help, for instance,
to hint user that the display port cable is probably detached (or)
the display port sink (viz., monitors ect.,) is un-powered.
Also helps to debug issues reported from field.
This change adds an additional attribute "hpd" to the existing
"displayport" attributes.
VESA DisplayPort Alt Mode on USB Type-C Standard defines how
HotPlugDetect(HPD) shall be supported on the USB-C connector
when operating in DisplayPort Alt Mode. This is a read only
node which reflects the current state of HPD.
Valid values:
- 1 when HPD’s logical state is high (HPD_High)
- 0 when HPD’s logical state is low (HPD_Low)
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20221211193755.1392128-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|