Re: [PATCH 1/2] soc: qcom: pd_mapper: Add X1E80100

Johan Hovold
2024-08-22T07:28:21Z

On Tue, Jul 30, 2024 at 11:04:58PM -0700, Chris Lew wrote:

> GLINK has a concept that is called "intents". An intent is an object
> that signifies that a remote channel is ready to receive a packet
> through GLINK. Intents can be pre-emptively queued, or they can be
> requested by the sending entity. GLINK will not try to send or it will
> block until there is an intent available.
>
> Intents are exchanged with GLINK_CMD_INTENT packets. When Linux receives
> one of these packets we add it to an idr "riids".
>
> Example sending call:
> pmic_glink_send() --> rpmsg_send() --> qcom_glink_send() -->
> __qcom_glink_send() --> qcom_glink_request_intent()
>
> In __qcom_glink_send(), we check if there are any available intents in
> "riids", if there aren't any intents we request an intent through
> qcom_glink_request_intent(). This sends a GLINK_CMD_RX_INTENT_REQ packet
> to the remote and waits for a GLINK_CMD_RX_INTENT_REQ_ACK packet in
> return. This ack packet will have a field that says whether the intent
> has been granted or not. When linux gets this ack packet, we will wake
> up the thread waiting in qcom_glink_request_intent().
>
> The ECANCELED comes from qcom_glink_request_intent() when we receive a
> GLINK_CMD_RX_INTENT_REQ_ACK that has granted == false.
>
> On the firmware, when a glink channel is registered they can optionally
> fill in a handler for GLINK_CMD_RX_INTENT_REQ packets. If this handler
> is not configured, then a default one will be used where all
> GLINK_CMD_RX_INTENT_REQ packets will be responded with
> GLINK_CMD_RX_INTENT_REQ_ACK and granted == false. If a channel is
> implemented this way, then the only thing Linux can do is wait and retry
> until the remote queues the intents on its own accord.
>
> This would be my current guess as to what's happening based on this not
> being consistent and only seen every couple of reboots. A stop path
> problem sounds like it should happen every time, and we should also see
> the remoteproc prints related to powering down the adsp. The above race
> should be applicable to all platforms but depends on the speed of the
> ADSP vs the CPU.

Thanks for the above. This indeed seems to match what I'm seeing as I
also reported here [1]:

[ 9.539415] 30000000.remoteproc:glink-edge: qcom_glink_handle_intent_req_ack - cid = 9, granted = 0
[ 9.561750] qcom_battmgr.pmic_glink_power_supply pmic_glink.power-supply.0: failed to request power notifications

[ 9.448945] 30000000.remoteproc:glink-edge: qcom_glink_handle_intent_req_ack - cid = 9, granted = 0
[ 9.461267] pmic_glink_altmode.pmic_glink_altmode pmic_glink.altmode.0: failed to send altmode request: 0x10 (-125)
[ 9.469241] qcom,apr 30000000.remoteproc:glink-edge.adsp_apps.-1.-1: Adding APR/GPR dev: gprsvc:service:2:1
[ 9.478968] pmic_glink_altmode.pmic_glink_altmode pmic_glink.altmode.0: failed to request altmode notifications: -125

I assume we do not want to have every client driver implement a retry
loop for the first communication with the remote end, so can this be
handled by the pmic_glink driver somehow? For example, by not forwarding
state changes until some generic request has gone through?

And what about the audio service errors:

[ 14.565059] PDR: avs/audio get domain list txn wait failed: -110
[ 14.571943] PDR: service lookup for avs/audio failed: -110

Does this seem to be a separate (but related) issue or just a different
symptom?

Johan

[1] https://lore.kernel.org/lkml/ZsRGV4hplvidpYji@hovoldconsulting.com/