Hi,
On 12 October 2015 at 12:50, Hans Verkuil <hverk...@xs4all.nl> wrote:
> On 10/06/2015 12:32 AM, Russell King - ARM Linux wrote:
>> On Mon, Sep 07, 2015 at 03:44:43PM +0200, Hans Verkuil wrote:
>>> + if (status & CEC_STATUS_TX_DONE) {
>>> + if (status & CEC_STATUS_TX_ERROR) {
>>> + dev_dbg(cec->dev, "CEC_STATUS_TX_ERROR set\n");
>>> + cec->tx = STATE_ERROR;
>>> + } else {
>>> + dev_dbg(cec->dev, "CEC_STATUS_TX_DONE\n");
>>> + cec->tx = STATE_DONE;
>>> + }
>>> + s5p_clr_pending_tx(cec);
>>> + }
>>
>> Your CEC implementation seems to be written around the idea that there
>> are only two possible outcomes from a CEC message - "done" and "error",
>> which get translated to:
>
> This code is for the Samsung exynos CEC implementation. Marek, is this all
> that the exynos CEC hardware returns?
The possible status values that are implemented in the CEC framework
are following:
+/* cec status field */
+#define CEC_TX_STATUS_OK (0)
+#define CEC_TX_STATUS_ARB_LOST (1 << 0)
+#define CEC_TX_STATUS_RETRY_TIMEOUT (1 << 1)
+#define CEC_TX_STATUS_FEATURE_ABORT (1 << 2)
+#define CEC_TX_STATUS_REPLY_TIMEOUT (1 << 3)
+#define CEC_RX_STATUS_READY (0)
The only two ones I could match with the Exynos CEC module status bits are
CEC_TX_STATUS_OK and CEC_TX_STATUS_RETRY_TIMEOUT.
The status bits in Exynos HW are:
- Tx_Error
- Tx_Done
- Tx_Transferring
- Tx_Running
- Tx_Bytes_Transferred
- Tx_Wait
- Tx_Sending_Status_Bit
- Tx_Sending_Hdr_Blk
- Tx_Sending_Data_Blk
- Tx_Latest_Initiator
- Tx_Wait_SFT_Succ
- Tx_Wait_SFT_New
- Tx_Wait_SFT_Retran
- Tx_Retrans_Cnt
- Tx_ACK_Failed
>
>>
>>> + case STATE_DONE:
>>> + cec_transmit_done(cec->adap, CEC_TX_STATUS_OK);
>>> + cec->tx = STATE_IDLE;
>>> + break;
>>> + case STATE_ERROR:
>>> + cec_transmit_done(cec->adap, CEC_TX_STATUS_RETRY_TIMEOUT);
>>> + cec->tx = STATE_IDLE;
>>
>> "okay" and "retry_timeout". So, if we have an adapter which can report
>> (eg) a NACK, we have to report it as the obscure "retry timeout" status?
>> Why this obscure naming - why can't we have something that uses the
>> terminology in the spec?
>>
>
> Actually, a NACK should lead to a re-transmission (up to 5 times), see CEC
> 7.1.
> The assumption of the CEC framework is that this is done by the CEC adapter
> driver, not by the framework. So if after repeated retransmissions there is
> still no Ack, the CEC_TX_STATUS_RETRY_TIMEOUT error is returned. I could
> change this to _MAX_RETRIES_REACHED if you prefer.
>
> The CEC_TX_STATUS_ macros were based on what the adv drivers support (except
> for CEC_TX_STATUS_REPLY_TIMEOUT which is specific to the framework).
>
> Regards,
>
> Hans
Best wishes,
Kamil
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