linux-kernel - Re: [PATCH] arm64: dts: qcom: sdm845-db845c: Mark cont splash memory region as reserved

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Date:   Mon, 10 Apr 2023 14:21:34 +0530
From:   Amit Pundir <amit.pundir@...aro.org>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     "Bryan O'Donoghue" <bryan.odonoghue@...aro.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Caleb Connolly <caleb.connolly@...aro.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        dt <devicetree@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] arm64: dts: qcom: sdm845-db845c: Mark cont splash memory
 region as reserved

On Thu, 9 Feb 2023 at 19:24, Dmitry Baryshkov
<dmitry.baryshkov@...aro.org> wrote:
>
> On 09/02/2023 14:22, Bryan O'Donoghue wrote:
> > On 09/02/2023 12:11, Bryan O'Donoghue wrote:
> >>> If the bootloader splash is enabled then this memory is used until the
> >>> DPU driver instructs MDP5 pipes to suck data from a newly assigned
> >>> address,
> >>> so there's a short window where it is.
> >>
> >> It seems a shame to reserve 30 something megabytes of memory for
> >> continuous splash unless we are actually using it is my point.
> >>
> >> If I'm running headless its just wasted memory.
> >
> > Couldn't we
> >
> > 1. Find reserved continuous splash memory
> > 2. Fee it in the MDP when we make the transition
>
> Qualcomm has investigated freeing the MDP/DPU cont_splash memory, but I
> fear that the end result was that it is not _that_ easy to free it. It
> is marked as reserved/no-map, so the kernel doesn't think about it as a
> memory region. Adding it back required hacking around that.

Hi Team,

This patch missed the v6.3 cut and I'm really hoping it to make it to
v6.4. Is there anything I can do it move it forward. Sorry if I missed
any action item assigned to me in the followup emails.

Regards,
Amit Pundir

>
> --
> With best wishes
> Dmitry
>