On 11/3/2023 8:44 PM, Bryan O'Donoghue wrote:
On 17/10/2023 14:18, Krishna Kurapati wrote:
The following are the requirements aimed in this implementation:
1. When enum in device mode, Glue/core must stay active.
2. When cable is connected but UDC is not written yet, then glue/core
must be suspended.
3. Upon removing cable in device mode, the disconnect event must be
generated and unblock runtime suspend for dwc3 core.
Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
Hi Bryan,
What happens to this code if you
static int count;
1. sleep in dwc3_probe for 10 milliseconds
2. return -EPROBE_DEFER
3. if count++ < 5 goto 1
i.e. if we simulate say waiting on a PHY driver to probe in dwc3_probe()
The vendor hooks are used in __dwc3_set_mode and role_switch_set calls
in core and drd files respectively. These are invoked only if we are OTG
capable. The drd_work is initialized in core_init_mode which is called
at the end of dwc3_probe. If dwc3_probe fails and gets deferred before
that, none of the vendor hooks will be fired and dwc3_qcom_probe is also
deferred.
However I see that if core_init_mode fails (the cleanup is already done
in drd to prevent set_role from getting invoked already), I need to
cleanup vendor hooks in error path of dwc3_probe().
and what happens if we introduce a 100 millsecond sleep into
dwc3_qcom_probe() - and run a fake disconnect event from
dwc3_qcom_probe_core() directly ?
In other words if make it that dwc3_probe() completes and struct
dwc3_glue_ops->notify_cable_disconnect() fires prior to
dwc3_qcom_probe_core() completing ?
i.e. I don't immediately see how you've solved the probe() completion
race condition here.
Just wanted to understand the situation clearly. Is this the sequence
you are referring to ?
1. dwc3_probe is successful and role switch is registered properly.
2. added delay after dwc3_qcom_probe_core and before interconnect_init
3. Between this delay, we got a disconnect notificiation from glink
4. We are clearing the qscratch reg in case of device mode and
un-registering notifier in case of host mode.
If so, firstly I don't see any issue if we process disconnect event
before qcom probe is complete. If we reached this stage, the clocks/gdsc
is definitely ON and register accesses are good to go.
If we are in host mode at this point, we would just unregister to
usb-core notifier and mark last busy. If we are in device mode, we would
just clear the hs_phy_ctrl reg of qscratch. After the 100ms delay you
mentioned we would call dwc3_remove anyways and cleanup the vendor
hooks. But is the concern here that, what if we enter runtime_suspend at
this point ?
Regards,
Krishna,
