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Diffstat (limited to 'Documentation/userspace-api/media/cec/cec-pin-error-inj.rst')
| -rw-r--r-- | Documentation/userspace-api/media/cec/cec-pin-error-inj.rst | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/cec/cec-pin-error-inj.rst b/Documentation/userspace-api/media/cec/cec-pin-error-inj.rst index 411d42a742f3..c02790319f3f 100644 --- a/Documentation/userspace-api/media/cec/cec-pin-error-inj.rst +++ b/Documentation/userspace-api/media/cec/cec-pin-error-inj.rst @@ -41,6 +41,9 @@ error injection status:: # <op> rx-clear clear all rx error injections for <op> # <op> tx-clear clear all tx error injections for <op> # + # RX error injection settings: + # rx-no-low-drive do not generate low-drive pulses + # # RX error injection: # <op>[,<mode>] rx-nack NACK the message instead of sending an ACK # <op>[,<mode>] rx-low-drive <bit> force a low-drive condition at this bit position @@ -53,6 +56,10 @@ error injection status:: # tx-custom-low-usecs <usecs> define the 'low' time for the custom pulse # tx-custom-high-usecs <usecs> define the 'high' time for the custom pulse # tx-custom-pulse transmit the custom pulse once the bus is idle + # tx-glitch-low-usecs <usecs> define the 'low' time for the glitch pulse + # tx-glitch-high-usecs <usecs> define the 'high' time for the glitch pulse + # tx-glitch-falling-edge send the glitch pulse after every falling edge + # tx-glitch-rising-edge send the glitch pulse after every rising edge # # TX error injection: # <op>[,<mode>] tx-no-eom don't set the EOM bit @@ -193,6 +200,14 @@ Receive Messages This does not work if the remote CEC transmitter has logical address 0 ('TV') since that will always win. +``rx-no-low-drive`` + The receiver will ignore situations that would normally generate a + Low Drive pulse (3.6 ms). This is typically done if a spurious pulse is + detected when receiving a message, and it indicates to the transmitter that + the message has to be retransmitted since the receiver got confused. + Disabling this is useful to test how other CEC devices handle glitches + by ensuring we will not be the one that generates a Low Drive. + Transmit Messages ----------------- @@ -327,3 +342,30 @@ Custom Pulses ``tx-custom-pulse`` Transmit a single custom pulse as soon as the CEC bus is idle. + +Glitch Pulses +------------- + +This emulates what happens if the signal on the CEC line is seeing spurious +pulses. Typically this happens after the falling or rising edge where there +is a short voltage fluctuation that, if the CEC hardware doesn't do +deglitching, can be seen as a spurious pulse and can cause a Low Drive +condition or corrupt data. + +``tx-glitch-low-usecs <usecs>`` + This defines the duration in microseconds that the glitch pulse pulls + the CEC line low. The default is 1 microsecond. The range is 0-100 + microseconds. If 0, then no glitch pulse will be generated. + +``tx-glitch-high-usecs <usecs>`` + This defines the duration in microseconds that the glitch pulse keeps the + CEC line high (unless another CEC adapter pulls it low in that time). + The default is 1 microseconds. The range is 0-100 microseconds. If 0, then + no glitch pulse will be generated.The total period of the glitch pulse is + ``tx-custom-low-usecs + tx-custom-high-usecs``. + +``tx-glitch-falling-edge`` + Send the glitch pulse right after the falling edge. + +``tx-glitch-rising-edge`` + Send the glitch pulse right after the rising edge. |