Re: [PATCH v8 01/11] firmware: arm_scmi: Add configurable polling mode for transports

From: Sudeep Holla
Date: Tue Dec 21 2021 - 15:23:43 EST


On Wed, Dec 22, 2021 at 01:08:54AM +0530, Pratyush Yadav wrote:
> Hi,
>
> On 20/12/21 07:56PM, Cristian Marussi wrote:
> > SCMI communications along TX channels can optionally be provided of a
> > completion interrupt; when such interrupt is not available, command
> > transactions should rely on polling, where the SCMI core takes care to
> > repeatedly evaluate the transport-specific .poll_done() function, if
> > available, to determine if and when a request was fully completed or
> > timed out.
> >
> > Such mechanism is already present and working on a single transfer base:
> > SCMI protocols can indeed enable hdr.poll_completion on specific commands
> > ahead of each transfer and cause that transaction to be handled with
> > polling.
> >
> > Introduce a couple of flags to be able to enforce such polling behaviour
> > globally at will:
> >
> > - scmi_desc.force_polling: to statically switch the whole transport to
> > polling mode.
> >
> > - scmi_chan_info.no_completion_irq: to switch a single channel dynamically
> > to polling mode if, at runtime, is determined that no completion
> > interrupt was available for such channel.
> >
> > Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
>
> This patch breaks linux-next build for me with LLVM.
>
> drivers/firmware/arm_scmi/driver.c:869:6: error: variable 'i_' is uninitialized when used within its own initialization [-Werror,-Wuninitialized]
> if (IS_POLLING_ENABLED(cinfo, info))
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/firmware/arm_scmi/driver.c:59:33: note: expanded from macro 'IS_POLLING_ENABLED'
> IS_TRANSPORT_POLLING_CAPABLE(i_)); \
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
> drivers/firmware/arm_scmi/driver.c:45:19: note: expanded from macro 'IS_TRANSPORT_POLLING_CAPABLE'
> typeof(__i) i_ = __i; \
> ~~ ^~~
> 1 error generated.
>

Thanks for the report. The bot complained last night and I have pushed
the update though not in time for linux-next today, must make it to
tomorrow's cut.

--
Regards,
Sudeep