linux-kernel - Re: [PATCH] firmware: arm_scmi: Give SMC transport precedence over mailbox

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Message-ID: <ZwUvV-w05UpQroRk@bogus>
Date: Tue, 8 Oct 2024 14:10:47 +0100
From: Sudeep Holla <sudeep.holla@....com>
To: Cristian Marussi <cristian.marussi@....com>
Cc: Florian Fainelli <florian.fainelli@...adcom.com>,
	linux-arm-kernel@...ts.infread.org, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Sudeep Holla <sudeep.holla@....com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>,
	"open list:SYSTEM CONTROL & POWER/MANAGEMENT INTERFACE" <arm-scmi@...r.kernel.org>,
	"moderated list:SYSTEM CONTROL & POWER/MANAGEMENT INTERFACE" <linux-arm-kernel@...ts.infradead.org>,
	justin.chen@...adcom.com, opendmb@...il.com,
	kapil.hali@...adcom.com, bcm-kernel-feedback-list@...adcom.com,
	Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH] firmware: arm_scmi: Give SMC transport precedence over
 mailbox

On Tue, Oct 08, 2024 at 01:26:53PM +0100, Cristian Marussi wrote:
> On Mon, Oct 07, 2024 at 10:07:46AM -0700, Florian Fainelli wrote:

[...]

> > There is no recovery without the patch, we are not giving up the arm_scmi
> > platform device because there is no mechanism to return -ENODEV and allow
> > any of the subsequent transport drivers enabled to attempt to take over the
> > platform device and probe it again.
> >
>
> Ok...so it is a workaround hack indeed....but it seems NOT to have bad
> side effects and there is definitely no cleaner way to make it bind
> properly...beside fixing your DTs for the future...

As I mentioned earlier, I am not against the change as it doesn't have
any other side-effects and just accidentally fixes the issue you have.
But it does sound like a hacky solution to your problem. What if some
other legit reason(theoretically) it needs to be reversed again in the
future. So I am still interested to see if we can fix it without this.

--
Regards,
Sudeep