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From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Tue, 23 May 2023 01:56:46 +0300
Message-ID: <CAA8EJppniEh3cFpi=AdK-i=KZcd=tzpPru0W4Vq9LJjJL8q=qQ@mail.gmail.com>
Subject: Re: [PATCH RFC 06/10] drm/panel/samsung-sofef01: Add panel driver for
 Sony Xperia 5 / 10 II
To:     Marijn Suijten <marijn.suijten@somainline.org>
Cc:     Neil Armstrong <neil.armstrong@linaro.org>,
        Sam Ravnborg <sam@ravnborg.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Caleb Connolly <caleb@connolly.tech>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        ~postmarketos/upstreaming@lists.sr.ht,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@somainline.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Martin Botka <martin.botka@somainline.org>,
        Jami Kettunen <jami.kettunen@somainline.org>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Kuogee Hsieh <quic_khsieh@quicinc.com>,
        Jessica Zhang <quic_jesszhan@quicinc.com>
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On Tue, 23 May 2023 at 01:32, Marijn Suijten
<marijn.suijten@somainline.org> wrote:
>
> On 2023-05-22 04:19:45, Dmitry Baryshkov wrote:
> > On 22/05/2023 00:23, Marijn Suijten wrote:
> > > This SOFEF01-M Display-IC driver supports two modes with different
> > > compatibles to differentiate between slightly different physical sizes
> > > (panels) found on the Xperia 5 (6.1") and 10 II (6.0").
> > >
> > > It is currently also used to hardcode significantly higher fake porches
> > > for the Xperia 5, which are unused in transfers due to this being a
> > > command-mode panel but do have an effect on the clock rates set by
> > > dsi_host.c.  Without higher clock rates this panel fails to achieve
> > > 60fps and has significant tearing artifacts, while the same calculated
> > > clock rate works perfectly fine on the Xperia 10 II.
>
> <snip>
>
> > > +/* Sony Xperia 5 (kumano bahamut) */
> > > +static const struct drm_display_mode samsung_sofef01_m_bahamut_mode = {
> > > +   /*
> > > +    * WARNING: These massive porches are wrong/useless for CMDmode
> > > +    * (and not defined in downstream DTS) but necessary to bump dsi
> > > +    * clocks higher, so that we can achieve proper 60fps without tearing.
> > > +    */
> > > +   .clock = (1080 + 156 + 8 + 8) * (2520 + 2393 + 8 + 8) * 60 / 1000,
> > > +   .hdisplay = 1080,
> > > +   .hsync_start = 1080 + 156,
> > > +   .hsync_end = 1080 + 156 + 8,
> > > +   .htotal = 1080 + 156 + 8 + 8,
> > > +   .vdisplay = 2520,
> > > +   .vsync_start = 2520 + 2393,
> > > +   .vsync_end = 2520 + 2393 + 8,
> > > +   .vtotal = 2520 + 2393 + 8 + 8,
> > > +   .width_mm = 61,
> > > +   .height_mm = 142,
> > > +};
> > > +
> > > +/* Sony Xperia 10 II (seine pdx201) */
> > > +static const struct drm_display_mode samsung_sofef01_m_pdx201_mode = {
> > > +   .clock = (1080 + 8 + 8 + 8) * (2520 + 8 + 8 + 8) * 60 / 1000,
> > > +   .hdisplay = 1080,
> > > +   .hsync_start = 1080 + 8,
> > > +   .hsync_end = 1080 + 8 + 8,
> > > +   .htotal = 1080 + 8 + 8 + 8,
> > > +   .vdisplay = 2520,
> > > +   .vsync_start = 2520 + 8,
> > > +   .vsync_end = 2520 + 8 + 8,
> > > +   .vtotal = 2520 + 8 + 8 + 8,
> > > +   .width_mm = 60,
> > > +   .height_mm = 139,
> > > +};
> > > +
> > > +static const struct of_device_id samsung_sofef01_m_of_match[] = {
> > > +   { .compatible = "samsung,sofef01-m-bahamut", .data = &samsung_sofef01_m_bahamut_mode },
> > > +   { .compatible = "samsung,sofef01-m-pdx201", .data = &samsung_sofef01_m_pdx201_mode },
> >
> > Are there really two panels? Can we use one mode for both usecases?
>
> See the commit description where I explained exactly this: the panels
> have different dimensions (6.1" vs 6.0", hence different DPI) and I also
> abuse this to hack in higher clock rates via fake porches.
>
> I just ended up on a scary website that supposedly contains the panel
> names:
>
> - Xperia 5 (bahamut, 6.1"): AMB609TC01
> - Xperia 10 II (pdx201, 6.0"): AMS597UT01

Great! From the patch description it was not obvious if those are two
different panels or a single panel with slight difference in the glass
cover. With these names in place (well, with two distinct names in
place) it makes sense.

-- 
With best wishes
Dmitry