On Tue 19 Nov 02:18 PST 2019, sibis@xxxxxxxxxxxxxx wrote:
> Hey Bjorn,
> Thanks for taking the time to
> review the series :)
>
> On 2019-11-19 12:10, Bjorn Andersson wrote:
> > On Mon 18 Nov 06:27 PST 2019, Sibi Sankar wrote:
> > > diff --git a/drivers/soc/qcom/pdr_interface.c
> > > b/drivers/soc/qcom/pdr_interface.c
> > [..]
> > > +static void pdr_indack_work(struct work_struct *work)
> > > +{
> > > + struct pdr_handle *pdr = container_of(work, struct pdr_handle,
> > > + indack_work);
> > > + struct pdr_list_node *ind, *tmp;
> > > + struct pdr_service *pds;
> > > +
> > > + list_for_each_entry_safe(ind, tmp, &pdr->indack_list, node) {
> > > + pds = ind->pds;
> > > + pdr_send_indack_msg(pdr, pds, ind->transaction_id);
> >
> > So when we et a ind_cb with the new status, we need to send an ack
> > request, which will result in a response, just to confirm that we got
> > the event?
> >
> > Seems like we should fix the qmi code to make it possible to send a
> > request from the indication handler and then we could simply ignore the
>
> yeah maybe having a provision to send custom requests back on
> indication would be the way to go. Not all indication need to be
> services with requests.
>
Let's put this on the todo list.
> > response. Or do we need to not pdr->status() until we get the response
> > for some reason?
>
> adsp waits on the ack response for a fixed duration and seems to throw
> a fatal err is the ack is not serviced. Hence holding back pd->status
> till we service the ack here.
>
You mean to ensure that someone sleeping in pd->status() doesn't delay
that until its too late?
[..]
> > > +int pdr_handle_init(struct pdr_handle *pdr,
> > > + int (*status)(struct pdr_handle *pdr,
> > > + struct pdr_service *pds))
> > > +{
> > [..]
> > > + pdr->servreg_wq = create_singlethread_workqueue("pdr_servreg_wq");
> > > + if (!pdr->servreg_wq)
> > > + return -ENOMEM;
> > > +
> > > + pdr->indack_wq = alloc_ordered_workqueue("pdr_indack_wq",
> > > WQ_HIGHPRI);
> >
> > The two workqueues means that we should be able to call pdr->status()
> > rom two concurrent contexts, I don't think our clients will expect that.
> >
>
> would creating another ordered wq to relay all the pd->status make
> sense?
>
I would prefer less work queues ;) But I presume you split out the
indack_wq in order to improve the likelihood of meeting the latency
requirements of the remote side.
Perhaps just wrap the status() calls with a status-mutex and then remove
that by reworking the QMI interface to allow us to remove the indack
work?
Regards,
Bjorn
