Re: [PATCH 1/2] dt-bindings: net: wireless: ath10k: add qcom,no-msa-ready-indicator prop

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Conor Dooley <conor@kernel.org>
Cc: Marc Gonzalez <mgonzalez@freebox.fr>,
	Kalle Valo <kvalo@kernel.org>,
	 Jeff Johnson <quic_jjohnson@quicinc.com>,
	ath10k <ath10k@lists.infradead.org>,
	 wireless <linux-wireless@vger.kernel.org>,
	DT <devicetree@vger.kernel.org>,
	 Rob Herring <robh+dt@kernel.org>,
	 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	 Pierre-Hugues Husson <phhusson@freebox.fr>,
	Jami Kettunen <jamipkettunen@gmail.com>,
	 Jeffrey Hugo <quic_jhugo@quicinc.com>
Subject: Re: [PATCH 1/2] dt-bindings: net: wireless: ath10k: add qcom,no-msa-ready-indicator prop
Date: Mon, 4 Mar 2024 21:37:00 +0200	[thread overview]
Message-ID: <CAA8EJpq5HQaO2E2Pd7yqUTsWyQ_pLDdyoWng8QmWTzYn5fv3PQ@mail.gmail.com> (raw)
In-Reply-To: <20240304-component-animator-e2ee0ab7574a@spud>

On Mon, 4 Mar 2024 at 21:34, Conor Dooley <conor@kernel.org> wrote:
>
> On Mon, Mar 04, 2024 at 05:21:37PM +0100, Marc Gonzalez wrote:
> > On 29/02/2024 19:40, Conor Dooley wrote:
> >
> > > On Wed, Feb 28, 2024 at 06:37:08PM +0200, Kalle Valo wrote:
> > >
> > >> Marc Gonzalez wrote:
> > >>
> > >>> As mentioned in my other reply, there are several msm8998-based
> > >>> devices affected by this issue. Is it not appropriate to consider
> > >>> a kernel-based work-around?
> > >>
> > >> Sorry, not following you here. But I'll try to answer anyway:
> > >>
> > >> I have understood that Device Tree is supposed to describe hardware, not
> > >> software. This is why having this property in DT does not look right
> > >> place for this. For example, if the ath10k firmware is fixed then DT
> > >> would have to be changed even though nothing changed in hardware. But of
> > >> course DT maintainers have the final say.
> > >
> > > I dunno, if the firmware affects the functionality of the hardware in a
> > > way that cannot be detected from the operating system at runtime how
> > > else is it supposed to deal with that?
> > > The devicetree is supposed to describe hardware, yes, but at a certain
> > > point the line between firmware and hardware is invisible :)
> > > Not describing software is mostly about not using it to determine
> > > software policy in the operating system.
> >
> > Recording here what was discussed a few days ago on IRC:
> >
> > If all msm8998 boards are affected, then it /might/ make sense
> > to work around the issue for ALL msm8998 boards:
> >
> > diff --git a/drivers/net/wireless/ath/ath10k/qmi.c b/drivers/net/wireless/ath/ath10k/qmi.c
> > index 0776e79b25f3a..9da06da518fb6 100644
> > --- a/drivers/net/wireless/ath/ath10k/qmi.c
> > +++ b/drivers/net/wireless/ath/ath10k/qmi.c
> > @@ -1076,6 +1076,9 @@ int ath10k_qmi_init(struct ath10k *ar, u32 msa_size)
> >       qmi->ar = ar;
> >       ar_snoc->qmi = qmi;
> >
> > +     if (of_device_is_compatible(of_root, "qcom,msm8998")
> > +             qmi->no_point_in_waiting_for_msa_ready_indicator = true;
> > +
> >       if (of_property_read_bool(dev->of_node, "qcom,msa-fixed-perm"))
> >               qmi->msa_fixed_perm = true;
> >
> >
> > Thus, anyone porting an msm8998 board to mainline would automatically
> > get the work-around, without having to hunt down the feature bit,
> > and tweak the FW files.
>
> How come the root node comes into this, don't you have a soc-specific
> compatible for the integration on this SoC?

No. Ath10k uses WiFi SoC as an SoC designator rather than the main SoC.

My 2c: I think it's easier to fix the firmware features bits, it's
more future proof (and error proof).

> (I am assuming that this is not the SDIO variant, given then it'd not be
> fixed to this particular implementation)

-- 
With best wishes
Dmitry