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From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
To: "Val Packett" <val@packett.cool>,
	"Bjorn Andersson" <andersson@kernel.org>,
	"Mathieu Poirier" <mathieu.poirier@linaro.org>,
	"Nathan Chancellor" <nathan@kernel.org>,
	"Nick Desaulniers" <nick.desaulniers+lkml@gmail.com>,
	"Bill Wendling" <morbo@google.com>,
	"Justin Stitt" <justinstitt@google.com>,
	"Matti Lehtimäki" <matti.lehtimaki@gmail.com>,
	"Luca Weiss" <luca@lucaweiss.eu>
Cc: "Vladimir Lypak" <vladimir.lypak@gmail.com>,
	"Barnabás Czémán" <barnabas.czeman@mainlining.org>,
	"Dmitry Baryshkov" <dmitry.baryshkov@oss.qualcomm.com>,
	~postmarketos/upstreaming@lists.sr.ht, linux@mainlining.org,
	phone-devel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-remoteproc@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH] remoteproc: qcom_wcnss: Fix handling the lack of PD regulators in v3
Date: Tue, 27 Jan 2026 14:06:15 +0100	[thread overview]
Message-ID: <6498dc50-c08a-4416-95ff-06a8ca7db6b0@oss.qualcomm.com> (raw)
In-Reply-To: <20260126235018.969140-1-val@packett.cool>

On 1/27/26 12:44 AM, Val Packett wrote:
> The changes introduced to handle single power domain platforms have
> swapped the info pointer increment from num_pd_vregs to num_pds, which
> doesn't change anything for pronto-v1 and v2 where they match, but as
> pronto-v3 has 2 power domains with no PD regulators at all, this would
> shift the pointer past the end of the array.
> 
> This showed up as a difference between GCC- and LLVM-compiled kernels
> on MSM8953/SDM632 devices, where only with LLVM one would get the
> "regulator request with no identifier" error, because the out-of-bounds
> memory ended up being zeroed. Fix by reverting that single line.
> 
> Fixes: 65991ea8a6d1 ("remoteproc: qcom_wcnss: Handle platforms with only single power domain")
> Signed-off-by: Val Packett <val@packett.cool>
> ---
> 
> I'm like 99% sure that this (old) line is correct and the change in this one line
> in 65991ea8a6d1 might've been an unintentional/stray one.
> 
> Still, please retest on MSM8974/MSM8226!
> 
> Thanks,
> ~val
> ---
>  drivers/remoteproc/qcom_wcnss.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/remoteproc/qcom_wcnss.c b/drivers/remoteproc/qcom_wcnss.c
> index ee18bf2e8054..5884c5a52af6 100644
> --- a/drivers/remoteproc/qcom_wcnss.c
> +++ b/drivers/remoteproc/qcom_wcnss.c
> @@ -454,7 +454,7 @@ static int wcnss_init_regulators(struct qcom_wcnss *wcnss,
>  	 * reserve extra space to manage them through the regulator interface.
>  	 */
>  	if (wcnss->num_pds) {
> -		info += wcnss->num_pds;
> +		info += num_pd_vregs;

The existing code is correct in that it skips the wcnss->num_pds
(i.e. "the number of PDs Linux managed to successfully attach to"), out
of the vregs table (which on all-but-pronto_v3_data is a superset of the
PD list, since 15 years ago the regulator framework was used to represent
all power-related RPM resources)

I believe the correct diff would be to check if the length of .pd_names
is >= the length of .vregs and say that it's the backwards-compat case
(which again, pronto_v3 isn't concerned by)

Konrad

      reply	other threads:[~2026-01-27 13:06 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-26 23:44 Val Packett
2026-01-27 13:06 ` Konrad Dybcio [this message]

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