Add a new capability CEC_CAP_NEEDS_HPD. If this capability is set then the hardware can only use CEC if the HDMI Hotplug Detect pin is high. Such hardware cannot handle the corner case in the CEC specification where it is possible to transmit messages even if no hotplug signal is present (needed for some displays that turn off the HPD when in standby, but still have CEC enabled). Typically hardware that needs this capability have the HPD wired to the CEC block, often to a 'power' or 'active' pin.
Showing the changes to include/uapi/linux (1 of 5 files). Show all
Unified · Split
| @@ -336,6 +336,8 @@ static inline int cec_is_unconfigured(__u16 log_addr_mask) · 335 unmodified lines | ||
| 336 | 336 | #define CEC_CAP_RC (1 << 4) |
| 337 | 337 | /* Hardware can monitor all messages, not just directed and broadcast. */ |
| 338 | 338 | #define CEC_CAP_MONITOR_ALL (1 << 5) |
| 339 | +/* Hardware can use CEC only if the HDMI HPD pin is high. */ | |
| 340 | +#define CEC_CAP_NEEDS_HPD (1 << 6) | |
| 339 | 341 | |
| 340 | 342 | /** |
| 341 | 343 | * struct cec_caps - CEC capabilities structure. |